Spampinato, A; Stacey, C; Mulholland, S; Robertson, B; Klein, H A; Huang, G; Barwood, G P; Gill, P (2924) An ion trap design for a space-deployable strontium-ion optical clock. Proceedings of the Royal Society A, 480 (2284). 20230593

Trigatzis, M; Knapp, M; Mulholland, S; Hockley, G; Barwood, G P; Huang, G; Klein, H A; Gill, P (2024) Progress towards a transportable laser-cooled Yb+ microwave clock. In: 2024 European Frequency and Time Forum (EFTF), 25-27 June 2024, Neuchatel, Switzerland.

Haji, M; Hill, I; Curtis, E A; Gill, P (2024) Holdover Atomic Clock Landscape Review. NPL Report. TQE 32

Cole, G D; Koller, S; Greve, C; Barwood, G P; Deutsch, C; Gaynor, P; Ghulinyan, M; Gill, P; Hendricks, R; Hill, I; Kundermann, S; le Goff, R; Lecomte, S; Meier, C; Pepponi, G; Schitt, S; Stenzel, C; Sutterlin, R; Voss, K; Zhukov, A (2024) Towards space-deployable laser stabilization systems based on vibration-insensitive cubic cavities with crystalline coatings. Optics Express, 32 (4). pp. 5380-5396.

Knapp, M; Walby, S; Haji, M; Foot, C; Gill, P (2023) Progress Towards a Compact Cold-Atom Microwave Clock. In: 2023 Joint Conference of the European Frequency and Time Forum and IEEE Frequency Control Symposium (EFTF/IFCS), 15-19 May 2023, Toyama, Japan.

Stacey, J; Barwood, G; Spampinato, A; Tsoulos, P; Robinson, C; Gaynor, P; Gill, P (2023) Laser frequency stabilisation for the LISA mission using a cubic cavity. Proceedings of SPIE, 12777. 127777F

Spampinato, A; Stacey, J; Mulholland, S; Robertson, B I; Klein, H G; Huang, G; Barwood, G P; Gill, P (2023) Progress towards development of a trapped strontium-ion space optical clock. Proceedings of the SPIE, 12335. 1233502

Barontini, G; Blackburn, L; Boyer, V; Butuc-Mayer, F; Calmet, X; Lopez-Urrutia, J R C; Curtis, E A; Darquie, B; Dunningham, J; Fitch, N J; Forgan, E M; Georgiou, K; Gill, P; Godun, R M; Goldwin, J; Guarrera, V; Harwood, A C; Hill, I R; Hendricks, R J; Jeong, M; Johnson, M Y H; Keller, M; Kozhiparambil Sajith, L P; Kuipers, F; Margolis, H S; Mayo, C; Newman, P; Parsons, A O; Prokhorov, L; Robertson, B I; Rodewald, J; Safronova, M S; Sauer, B E; Schioppo, M; Sherril, N; Stadnik, Y V; Szymaniec, K; Tarbutt, M R; Thompson, R C; Tofful, A; Tunesi, J; Vecchio, A; Wang, Y; Worm, S (2022) Measuring the stability of fundamental constants with a network of clocks. EPJ Quantum Technology, 9. 12

Hill, I R; Hendricks, R J; Donnellan, S; Gaynor, P; Allen, B; Barwood, G P; Gill, P (2021) Dual-axis cubic cavity for drift-compensated multi-wavelength laser stabilisation. Optics Express, 29 (22). pp. 36758-36768.

Hobson, R; Bowden, W; Vianello, A; Silva, A; Baynham, C F A; Margolis, H S; Baird, P E G; Gill, P; Hill, I R (2020) A strontium optical lattice clock with 1 × 10−17 uncertainty and measurement of its absolute frequency. Metrologia, 57 (6). 065026 ISSN 0026-1394

Roberts, B M; Delva, P; Al-Masoudi, A; Amy-Klein, A; Bærentsen, C; Baynham, C F A; Benkler, E; Bilicki, S; Bize, S; Bowden, W; Calvert, J; Cambier, V; Cantin, E; Curtis, E A; Dörscher, S; Favier, M; Frank, F; Gill, P; Godun, R M; Grosche, G; Guo, C; Hees, A; Hill, I R; Hobson, R; Huntemann, N; Kronjäger, J; Koke, S; Kuhl, A; Lange, R; Legero, T; Lipphardt, B; Lisdat, C; Lodewyck, J; Lopez, O; Margolis, H S; Álvarez-Martínez, H; Meynadier, F; Ozimek, F; Peik, E; Pottie, P-E; Quintin, N; Sanner, C; De Sarlo, L; Schioppo, M; Schwarz, R; Silva, A; Sterr, U; Tamm, Chr; Le Targat, R; Tuckey, P; Vallet, G; Waterholter, T; Xu, D; Wolf, P (2020) Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks. New Journal of Physics, 22 (9). 093010 ISSN 1367-2630

Riedel, F; Al-Masoudi, A; Benkler, E; Dörscher, S; Gerginov, V; Grebing, C; Häfner, S; Huntemann, N; Lipphardt, B; Lisdat, C; Peik, E; Piester, D; Sanner, C; Tamm, C; Weyers, S; Denker, H; Timmen, L; Voigt, C; Calonico, D; Cerretto, G; Costanzo, G A; Levi, F; Sesia, I; Achkar, J; Guéna, J; Abgrall, M; Rovera, D; Chupin, B; Shi, C; Bilicki, S; Bookjans, E; Lodewyck, J; Le Targat, R; Delva, P; Bize, S; Baynes, F N; Baynham, C F A; Bowden, W; Gill, P; Godun, R M; Hill, I R; Hobson, R; Jones, J M; King, S A; Nisbet-Jones, P B R; Rolland, A; Shemar, S L; Whibberley, P B; Margolis, H S (2020) Direct comparisons of European primary and secondary frequency standards via satellite techniques. Metrologia, 57 (4). 045005 ISSN 0026-1394

Sanjuan, Josep; Abich, Klaus; Gohlke, Martin; Resch, Andreas; Schuldt, Thilo; Wegehaupt, Timm; Barwood, G P; Gill, P; Braxmaier, Claus (2020) Long-term stable optical cavity for special relativity tests in space: erratum (Optics Express, (2019), Vol. 27, Issue 25, p36206 - 36220). Optics Express, 28 (6). p. 7917. ISSN 1094-4087

Bowden, W; Hobson, R; Hill, I R; Vianello, A; Schioppo, M; Silva, A; Margolis, H S; Baird, P E G; Gill, P (2019) A pyramid MOT with integrated optical cavities as a cold atom platform for an optical lattice clock. Scientific Reports, 9 (1). 11704 ISSN 2045-2322

Tino, G M; Bassi, A; Bianco, G; Bongs, K; Bouyer, P; Cacciapuoti, L; Capozziello, S; Chen, X; Chiofalo, M L; Derevianko, A; Ertmer, W; Gaaloul, N; Gill, P; Graham, P W; Hogan, J M; Iess, L; Kasevich, M A; Katori, H; Klempt, C; Lu, X; Ma, L S; Müller, H; Newbury, N R; Oates, C W; Peters, A; Poli, N; Rasel, E M; Rosi, G; Roura, A; Salomon, C; Schiller, S; Schleich, W; Schlippert, D; Schreck, F; Schubert, C; Sorrentino, F; Sterr, U; Thomsen, J W; Vallone, G; Vetrano, F; Villoresi, P; von Klitzing, W; Wilkowski, D; Wolf, P; Ye, J; Yu, N; Zhan, M (2019) SAGE: A proposal for a space atomic gravity explorer. The European Physical Journal D, 73 (11). 228 ISSN 1434-6060

Curtis, E A; Bradley, T; Barwood, G P; Edwards, C S; Wheeler, N V; Phelan, R; Richardson, D J; Petrovich, M N; Gill, P (2018) Laser frequency stabilization and spectroscopy at 2051 nm using a compact CO2-filled Kagome hollow core fiber gas-cell system. Optics Express, 26 (22). pp. 28621-28633. ISSN 1094-4087

Mulholland, S; Donnellan, S; Barwood, G P; Gentle, D; Huang, Guilong; Klein, H A; Patel, P; Walsh, G; Baird, P.E.G.; Gill, P (2018) A Portable Microwave Clock Using Laser-Cooled Trapped 171Yb+Ions. In: 2018 IEEE International Frequency Control Symposium (IFCS), 21-24 May 2018, Olympic Valley, CA, USA.

Aldous, Matthew; Viswam, Sruthi; Bass, Jonathan; Menchetti, Marco; Ubaid, Qasim; Jones, Jonathan; Morris, David; Molony, Peter; Gellesch, Markus; Bongs, Kai; Singh, Yeshpal; Hill, I; Williams, R; Gill, P (2018) Route to a Portable Optical Clock. In: 2018 IEEE International Frequency Control Symposium (IFCS), 21-24 May 2018, Olympic Valley, CA, USA.

Hill, I R; Hobson, R; Bowden, W; Schioppo, M; Silva, A; Gill, P; Margolis, H; Huillery, P H; Jones, M P A (2018) Sr Lattice Clocks at NPL. In: 2018 IEEE International Frequency Control Symposium (IFCS), 21-24 May 2018, Olympic Valley, CA, USA.

Godun, R M; Baynham, C F A; Jones, J M; King, S A; Nisbet-Jones, P B R; Baynes, F; Rolland, A; Baird, P E G; Bongs, K; Gill, P; Petit, G; Margolis, H S (2018) Absolute frequency measurement of the ytterbium ion E3 optical clock transition using international atomic time. In: 2018 European Frequency and Time Forum (EFTF), 10-12 April 2018, Turin, Italy.

Riehle, F; Gill, P; Arias, F; Robertson, L (2018) The CIPM list of recommended frequency standard values: guidelines and procedures. Metrologia, 55 (2). pp. 188-200.

Baynham, C F A; Godun, R M; Jones, J M; King, S A; Nisbet-Jones, P B R; Baynes, F; Rolland, A; Baird, P E G; Bongs, K; Gill, P; Margolis, H S (2018) Absolute frequency measurement of the S-2(1/2) - F-2(7/2) optical clock transition in Yb-171(+) with an uncertainty of 4 x 10(-16) using a frequency link to international atomic time. Journal of Modern Optics, 65 (5-6). pp. 585-591. ISSN 0950-0340

Bowden, W; Hobson, R; Huillery, P; Gill, P; Jones, M P A; Hill, I (2017) Rydberg electrometry for optical lattice clocks. Physical Review A, 96 (2). 023419

Bowden, W; Hobson, R; Gill, P; Hill, I R; Huillery, P H; Jones, M P A (2017) Rydberg spectroscopy for DC stark shift characterisation in optical lattice clocks. In: 2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC), 9-13 July 2017, Besancon, France.

Barwood, G P; Gill, P; Klein, H A; Hosaka, K; Huang, G; Lea, S N; Margolis, H S; Szymaniec, K; Walton, B R (2017) Trapped strontium ion optical clocks. Proceedings of the SPIE, 10567. 105672U

Bowden, W; Hill, I R; Baird, P E G*; Gill, P (2017) Note: a high-performance, low-cost laser shutter using a piezoelectric cantilever actuator. Rev. Sci. Instrum., 88 (1). 016102

Delva, P*; Lodewyck, J*; Bilicki, S*; Bookjans, E*; Vallet, G*; Le Target, R*; Pottie, P E*; Guerlin, C*; Meynadier, F*; Le Poncin-Lafitte, C*; Lopez, O*; Amy-Klein, A*; Lee, W K*; Quintin, N*; Lisdat, C*; Al-Masoudi, A*; Dorscher, S*; Grebing, C*; Grosche, G*; Kuhl, A*; Raupach, S*; Sterr, U*; Hill, I R; Hobson, R; Bowden, W; Kronjager, J; Marra, G; Rolland, A; Baynes, F N; Margolis, H S; Gill, P (2017) Test of special relativity using a fiber network of optical clocks. Phys. Rev. Lett., 118 (22). 221102

Margolis, H S; Gill, P (2016) Determination of optimized frequency and frequency ratio values from over-determined sets of clock comparison data. J. Phys.: Conf. Ser., 723. 012060

Origlia, S*; Schiller, S*; Pramod, M S*; Smith, L*; Singh, Y*; He, W*; Viswam, S*; Swierad, D*; Hughes, J*; Bongs, K*; Sterr, U*; Lisdat, C*; Vogt, S*; Bize, S*; Lodewyck, J*; Le Targat, R*; Holleville, D*; Venon, B*; Gill, P; Barwood, G P; Hill, I R; Ovchinnikov, Y B; Kulosa, A*; Ertmer, W*; Rasel, E M*; Stuhler, J*; Kaenders, W* (2016) Development of a strontium optical lattice clock for the SOC mission on the ISS. Proc. SPIE - Int. Soc. Opt. Eng., 9900. 990003

Leute, J*; Huntemann, N*; Lipphardt, B*; Tamm, C*; Nisbet-Jones, P B R; King, S A; Godun, R M*; Jones, J M*; Margolis, H S; Whibberley, P B; Wallin, A*; Merimaa, M*; Gill, P; Peik, E* (2016) Frequency comparison of 171Yb+ ion optical clocks at PTB and NPL via GPS PPP. IEEE Trans. Ultrason. Feroelectr. Freq. Control, 63 (7). pp. 981-985.

Gill, P (2016) Is the time right for a redefinition of the second by optical atomic clocks? J. Phys.: Conf. Ser., 723 (1). 012053

Hobson, R; Bowden, W; King, S A; Baird, P E G*; Hill, I R; Gill, P (2016) Modified hyper-Ramsey methods for the elimination of probe shifts in optical clocks. Phys. Rev. A, 93 (1). 010501

Barwood, G P; Huang, G; King, S A; Klein, H A; Gill, P (2016) Trapped-ion 88Sr+ optical clock systematic uncertainties - AC Stark shift determination. J. Phys.: Conf. Ser., 723. 012024

Bongs, K*; Boyer, V*; Cruise, M A*; Freise, A*; Holynski, M*; Hughes, J*; Kaushik, A*; Lien, Y H*; Niggebaum, A*; Perea-Ortiz, M*; Petroz, P*; Plant, S*; Singh, Y*; Stabrawa, A*; Paul, D J*; Sorel, M*; Cumming, D R S*; Marsh, J H*; Bowtell, R W*; Bason, M G*; Beardsley, R P*; Campion, R P*; Brookes, M J*; Fernholz, T*; Fromhold, T M*; Hackermuller, L*; Kruger, P*; Li, X*; Maclean, J O*; Mellor, C J*; Novikov, S V*; Orucevic, F*; Rushforth, A W*; Welch, N*; Benson, T M*; Wildman, R D*; Greegarde, T*; Himsworth, M*; Ruostekoski, J*; Smith, P*; Tropper, A*; Griffin, P F*; Arnold, A S*; Riis, E*; Hastie, J E*; Paboeuf, D*; Parrotta, D C*; Garraway, B M*; Pasquazi, A*; Peccianti, M*; Hensinger, W*; Potter, E*; Nizamani, A H*; Bostock, H*; Blanco, A R*; Sinuco-Leon, G*; Hill, I R; Williams, R A; Gill, P; Hempler, N*; Malcolm, G P A*; Cross, T*; Kock, B O*; Maddox, S*; John, P* (2016) The UK national quantum technology hub in sensors and metrology. Proc. SPIE - Int. Soc. Opt. Eng., 9900. 990009

Hill, I R*; Hobson, R*; Bowden, W*; Bridge, E M*; Donnellan, S*; Curtis, E A*; Gill, P (2016) A low maintenance Sr optical lattice clock. J. Phys.: Conf. Ser., 723 (1). 012019

Nisbet-Jones, P B R; King, S A; Jones, J M; Godun, R M; Baynham, C F A; Bongs, K*; Dolezal, M*; Balling, P*; Gill, P (2016) A single-ion trap with minimized ion-environment interactions. Appl. Phys. B, Laser Opt., 122 (3). p. 57.

Dolezal, M*; Balling, P*; Nisbet-Jones, P B R; King, S A; Jones, J M; Klein, H A; Gill, P; Lindvall, T*; Wallin, A E*; Merimaa, M*; Tamm, C*; Sanner, C*; Huntemann, N*; Scharnhorst, N*; Leroux, I D*; Schmidt, P O*; Burgermeister, T*; Mehlstaubler, T E*; Peik, E* (2015) Analysis of thermal radiation in ion traps for optical frequency standards. Metrologia, 52 (6). pp. 842-856.

Barwood, G P; Huang, G; Klein, H A; Gill, P (2015) Automatic minimisation of micromotion in a 88Sr+ optical clock. Meas. Sci. Technol., 26 (7). 075203

Bongs, K*; Singh, Y*; Smith, L*; He, W*; Kock, O*; Swierad, D*; Hughes, J*; Schiller, S*; Alighanbari, S*; Origlia, S*; Vogt, S*; Sterr, O*; Lisdat, C*; Le Targat, R*; Lodewyck, J*; Holleville, D*; Venon, B*; Bize, S*; Barwood, G P; Gill, P; Hill, I R*; Ovchinnikov, Y B; Poli, N*; Tino, G M*; Stuhler, J*; Kaenders, W* (2015) Development of a strontium optical lattice clock for the SOC mission on the ISS. Comptes Rendus Physique, 16 (5). pp. 553-564.

Johnson, L A M; Gill, P; Margolis, H S (2015) Evaluating the performance of the NPL femtosecond frequency combs: agreement at the 10 -21 level. Metrologia, 52 (1). pp. 62-71.

Barwood, G P; Huang, G; King, S A; Klein, H A; Gill, P (2015) Frequency noise processes in a strontium ion optical clock. J. Phys. B, At. Mol. Opt. Phys., 48 (3). 035401

Fitzau, O*; Herper, M*; Giesberts, M*; Nicklaus, K*; Barwood, G P; Williams, R A; Gill, P; Koegel, H*; Hoffman, H D* (2015) High stability single-frequency Yb fiber amplifier for next generation gravity missions. Proc. SPIE - Int. Soc. Opt. Eng., 9344. 93440B

Margolis, H S; Gill, P (2015) Least-squares analysis of clock frequency comparison data to deduce optimized frequency and frequency ratio values. Metrologia, 52 (5). pp. 628-634.

Barwood, G P; Huang, G; Klein, H A; Johnson, L A M; King, S A; Margolis, H S; Szymaniec, K; Gill, P (2014) Agreement between two 88Sr+ optical clocks to 4 parts in 10^17. Phys. Rev. A, 89 (5). 050501

Godun, R M; Nisbet-Jones, P B R; Jones, J M; King, S A; Johnson, L A M; Margolis, H S; Szymaniec, K; Lea, S N; Bongs, K*; Gill, P (2014) Frequency ratio of two optical clock transitions in 171Yb+ and constraints on the time-variation of fundamental constants. Phys. Rev. Lett., 113 (21). 210801

Parker, B; Marra, G; Johnson, L A M; Margolis, H S; Webster, S A; Wright, L; Lea, S N; Gill, P; Bayvel, P* (2014) Transportable cavity-stabilised laser system for optical carrier frequency transmission experiments. Appl. Opt., 53 (35). pp. 8157-8166.

Hill, I R*; Ovchinnikov, Y B; Bridge, E M*; Curtis, E A*; Gill, P (2014) Zeeman slowers for strontium based on permanent magnets. J. Phys. B, At. Mol. Opt. Phys., 47 (7). 075006

Schiller, S*; Gorlitz, A*; Abou-Jaoudeh, C*; Mura, G*; Franzen, T*; Nevsky, A*; Alighanbari, S*; Chen, Q*; Ernsting, I*; Poli, N*; Schioppo, M*; Tino, G M*; Sterr, U*; Vogt, S*; Falke, S*; Lisdat, C*; Gill, P; Barwood, G P; Ovchinnikov, Y B; Rasel, E*; Kulosa, A*; Bongs, K*; Singh, Y*; Calonico, D*; Levi, F*; Stuhler, J*; Kaenders, W*; Bize, S*; Holtzwarth, R* (2013) Development of compact lattice optical clocks toward future space clocks. In: Lasers & Electro-Optics. Europe & International Quantum Electronics Conference (CLEO EUROPE/IQEC 2013), 12-16 May 2013, Munich, Germany.

Margolis, H S; Godun, R M*; Gill, P; Johnson, L A M*; Shemar, S L*; Whibberley, P B; Calonico, D*; Levi, F*; Lorini, L*; Pizzocaro, M*; Delva, P*; Bize, S*; Achkar, J*; Denker, H*; Timmen, L*; Voigt, C*; Falke, S*; Piester, D*; Lisdat. C*,; Sterr, U*; Vogt, S*; Weyers, S*; Gersl, J*; Lindvall, T*; Merimaa, M* (2013) International timescales with optical cloacks (ITOC). In: 2013 Joint European Frequency and Time Forum & International Frequency COntrol Symposium (EFTF/IFC 2013), 21-25 July 2013, Prague, Czech Republic.

Hill, I R*; Ovchinnikov, Y B; Bridge, E M*; Curtis, E A*; Donnellan, S*; Gill, P (2013) A simple, configurable, permanent magnet Zeeman Slower for Sr. In: 2012 European Frequency and Time Forum (EFTF 2012), 23-27 April 2012, Gothenburg, Sweden.

Schiller, S*; Gorlitz, A*; Nevsky, A*; Alighanbari, S*; Vasilyev, S*; Abou-Jaoudeh, C*; Mura, G*; Franzen, T*; Sterr, U*; Falke, S*; Lisdat, C*; Rasel, E*; Kulosa, A*; Bize, S*; Lodewyck, J*; Tino, G M*; Poli, N*; Schioppo, M*; Bongs, K*; Singh, Y*; Gill, P; Barwood, G P; Ovchinnikov, Y B; Stuhler, J*; Kaenders, W*; Braxmaier, C*; Holzwarth, R*; Donati, A*; Lecomte, S*; Calonico, D*; Levi, F* (2013) The space optical clocks project: development of high-performance transportable and breadboard optical clocks and advanced subsystems. In: 2012 European Frequency and Time Forum (EFTF 2012), 23-27 April 2012, Gothenburg, Sweden.

See, P; Wilpers, G; Gill, P; Sinclair, A G (2013) Fabrication of a monolithic array of three dimensional Si-based ion traps. J. Microelectrochem. Syst., 22 (5). pp. 1180-1189.

Poli, N*; Oates, C W*; Gill, P; Tino, G M* (2013) Optical atomic clocks. Rivista del Nuovo Cimento, 36 (12). pp. 555-624.

Nevsky, A*; Alighanbari, S*; Chen, Q F*; Ernstring, I*; Vasilyev, S*; Schiller, S*; Barwood, G P; Gill, P; Poli, N*; Tino, G M* (2013) Robust frequency stabilization of multiple spectroscopy lasers with large and tunable offset frequencies. Opt. Lett., 38 (22). pp. 4903-4906.

Lessing, M*; Margolis, H S; Brown, C T A*; Gill, P; Marra, G (2013) Suppression of amplitude-to-phase noise conversion in balanced optical-microwave phase detectors. Opt. Express, 21 (22). pp. 27057-27062.

Wilpers, G; See, P; Gill, P; Sinclair, A G (2013) A compact UHV package for microfibricated ion-trap arrays with direct electronic air-side access. Appl. Phys. B, 111 (1). pp. 21-28.

King, S A; Godun, R M; Webster, S A; Margolis, H S; Johnson, L A M; Szymaniec, K; Baird, P E G*; Gill, P (2012) Absolute frequency measurement of the 2S- 1/2 - 2F-2 7/2) electric octupole transition in a single ion of Yb-171(+) with 10(-15) fractional uncertainty. New J. Phys., 14 (1). 013045

Barwood, G P; Gill, P; Huang, G; Klein, H A (2012) Automatic laser control for a 88Sr+ optical frequency standard. Meas. Sci. Technol., 23 (5). 055201

Barwood, G P; Gill, P; Huang, G; Klein, H A (2012) Characterization of a 88Sr+ optical frequency standard at 445 THz by two-trap comparison. In: 2012 Conference on Precision Electromagnetic Measurements (CPEM 2012), 1-6 July 2012, Washington DC, USA.

Edwards, C S; Barwood, G P; Patel, P D; Gill, P; Benabid, F*; Wheeler, N V*; Tandoi, G*; Ironside, C N* (2012) Development and evaluation of compact acetylene frequency standards. In: 2012 Conference on Precision Electromagnetic Measurements (CPEM 2012), 1-6 July 2012, Washington DC, USA.

Burt, E*; Gill, P (2012) Introduction to the special issue on the 2011 joint IEEE International Frequency Control Symposium and European Frequency and Time Forum. IEEE Trans. Ultrason. Feroelectr. Freq. Control, 59 (3). pp. 332-333.

Gill, P; Riehle, F* (2012) Possibilities for a future redefinition of the second. In: 2012 Conference on Precision Electromagnetic Measurements (CPEM 2012), 1-6 July 2012, Washington DC, USA.

Wilpers, G; See, P; Gill, P; Sinclair, A G (2012) A monolithic array of three-dimensional ion traps fabricated with conventional semiconductor technology. Nature Nanotechnol., 7 (9). pp. 572-576.

Webster, S A; Gill, P (2011) Force-insensitive optical cavity. Opt. Lett., 36 (18). pp. 3572-3574.

Marra, G; Slavik, R*; Margolis, H S; Lea, S N; Petropoulos, P*; Richardson, D J*; Gill, P (2011) High resolution microwave frequency transfer over a 86 km-long optical fiber network using a mode-locked laser.. Opt. Lett., 36 (4). pp. 511-513.

Gill, P (2011) When should we change the definition of the second? Philos. Trans. R. Soc. Lond. A, Math. Phys. Eng. Sci., 369 (1953). pp. 4109-4130.

Tsatourian, V; Margolis, H S; Marra, G; Reid, D T*; Gill, P (2010) Common-path self-referencing interferometer for carrier-envelope offset frequency stabilization with enhanced noise immunity. Opt. Lett., 35 (8). pp. 1209-1211.

Webster, S A; Godun, R; King, S; Huang, G L; Walton, B; Tsatourian, V; Margolis, H S; Lea, S N; Gill, P (2010) Frequency measurement of the S-2(1/2)-D-2(3/2) electric quadrupole transition in a single Yb-171(+) ion. IEEE Trans. Ultrason. Feroelectr. Freq. Control, 57 (3). pp. 592-599.

Marra, G; Margolis, H S; Lea, S N; Gill, P (2010) High-stability microwave frequency transfer by propagation of an optical frequency comb over 50 km of optical fiber. Opt. Lett., 35 (7). pp. 1025-1027.

Tsatourian, V; Margolis, H S; Marra, G; Reid, D T*; Gill, P (2010) Noise-insensitive self-referencing interferometer for carrier-envelope offset frequency stabilization of a Ti:sapphire laser. In: Lasers and Electro-optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), 2010, 16-21 May 2010, Sam Jose, USA.

Appourchaux, T*; Burston, R*; Chen, Y B*; Cruise, M*; Dittus, H*; Foulon, B*; Gill, P; Gizon, L*; Klein, H A; Klioner, S*; Kopeikin, S*; Kruger, H*; Lammerzahl, C*; Lobo, A*; Luo, X L*; Margolis, H S; Ni, W T*; Paton, A P*; Peng, Q H*; Peters, A*; Rasel, E*; Rudiger, A*; Samain, E*; Selig, H*; Shaul, D*; Sumner, T*; Theil, S*; Touboul, P*; Turyshev, S*; Wang, H T*; Wang, L*; Wen, L Q*; Wicht, A*; Wu, J*; Zhang, X M*; Zhao, C* (2009) Astrodynamical Space Test of Relativity Using Optical Devices I (ASTROD I)-A class-M fundamental physics mission proposal for Cosmic Vision 2015-2025. Exp. Astron., 23 (2). pp. 491-527.

Edwards, C S; Patel, P D; Barwood, G P; Gill, P (2009) Development of a compact 1.55 µm acetylene standard using a widely tunable DSDBR diode laser. In: 9th Optical Fibre Measurement Conference (OFMC) Digest, 16-18 September 2009, NPL, Teddington,UK.

Schiller, S*; Tino, G M*; Gill, P; Salomon, C*; Sterr, U*; Peik, E*; Nevsky, A*; Gorlitz, A*; Svehla, D*; Ferrari, G*; Poli, N*; Lusanna, L*; Klein, H A; Margolis, H S; Lemonde, P*; Laurent, P*; Santarelli, G*; Clairon, A*; Ertmer, W*; Rasel, E*; Muller, J*; Iorio, L*; Lommerzahl, C*; Dittus, H*; Gill, E*; Rothacher, M*; Flechner, F*; Schreiber, U*; Flambaum, V*; Ni, W T*; Liu, L*; Chen, X Z*; Chen, J B*; Gao, K L*; Cacciapuoti, L*; Holzwarth, R*; Hess, M P*; Schafer, W* (2009) Einstein Gravity Explorer-a medium-class fundamental physics mission. Exp. Astron., 22 (2). pp. 573-610.

Hosaka, K*; Webster, S A; Stannard, A*; Walton, B R; Margolis, H S; Gill, P (2009) Frequency measurement of the 2S1/2 - 2D3/2 electric quadrupole transition in a single 171Yb+ ion. Phys. Rev. A, 79 (3). 033403

Amelino-Camelia, G*; Aplin, K*; Arndt, M*; Barrow, J D*; Bingham, R J*; Borde, C*; Bouyer, P*; Caldwell, M*; Cruise, A M*; Damour, T*; D'Arrigo, P*; Dittus, H*; Ertmer, W*; Foulon, B*; Gill, P; Hammond, G D*; Hough, J*; Jentsch, C*; Johann, U*; Jetzer, P*; Klein, H A; Lambrecht, A*; Lamine, B*; Lammerzahl, C*; Lockerbie, N*; Loeffler, F*; Mendonca, J T*; Mester, J*; Ni, W T*; Pegrum, C*; Peters, A*; Rasel, E*; Reynaud, S*; Shaul, D*; Sumner, T J*; Theil, S*; Torrie, C*; Touboul, P*; Trenkel, C*; Vitale, S*; Vodel, W*; Wang, C*; Ward, H*; Woodgate, A* (2009) GAUGE: the GrAnd Unification and Gravity Explorer. Exp. Astron., 23 (2). pp. 549-572.

Ertmer, W*; Schubert, C*; Wendrich, T*; Gilowski, M*; Zaiser, M*; von Zoest, T*; Rasel, E*; Borde, C J*; Clairon, A*; Laurent, P*; Lemonde, P*; Santarelli, G*; Schleich, W*; Cataliotti, F S*; Inguscio, M*; Poli, N*; Sorrentino, F*; Modugno, C*; Tino, G M*; Gill, P; Klein, H A; Margolis, H S; Reynaud, S*; Salomon, C*; Lambrecht, A*; Peik, E*; Jentsch, C*; Johann, U*; Rathke, A*; Bouyer, P*; Cacciapuoti, L*; De Natale, P*; Christophe, B*; Foulon, B*; Touboul, P*; Maleki, L*; Yu, N*; Turyshev, S G*; Anderson, J D*; Schmidt-Kaler, F*; Walser, R*; Vigue, J*; Buchner, M*; Angonin, M C*; Delva, P*; Tourrenc, P*; Bingham, R*; Kent, B*; Wicht, A*; Wang, L J*; Bongs, K*; Dittus, H*; Lammerzahl, C*; Theil, S*; Sengstock, K*; Peters, A*; Muller, T*; Arndt, M*; Iess, L*; Bondu, F*; Brillet, A*; Samain, E*; Chiofalo, M L*; Levi, F*; Calonico, D* (2009) Matter wave explorer of gravity (MWXG). Exp. Astron., 23 (2). pp. 611-649.

Wolf, P*; Borde, C J*; Clairon, A*; Duchayne, L*; Landragin, A*; Lemonde, P*; Santarelli, G*; Ertmer, W*; Rasel, E*; Cataliotti, F S*; Inguscio, M*; Tino, G M*; Gill, P; Klein, H A; Reynaud, S*; Salomon, C*; Peik, E*; Bertolami, O*; Gil, P*; Paramos, J*; Jentsch, C*; Johann, U*; Rathke, A*; Bouyer, P*; Cacciapuoti, L*; Izzo, D*; De Natale, P*; Christophe, B*; Touboul, P*; Turyshev, S G*; Anderson, J*; Tobar, M E*; Schmidt-Kaler, F*; Vigue, J*; Madej, A A*; Marmet, L*; Angonin, M C*; Delva, P*; Tourrenc, P*; Metris, G*; Muller, H*; Walsworth, R*; Lu, Z H*; Wang, L J*; Bongs, K*; Toncelli, A*; Tonelli, M*; Dittus, H*; Lammerzahl, C*; Galzerano, G*; Laporta, P*; Laskar, J*; Fienga, A*; Roques, F*; Sengstock, K* (2009) Quantum physics exploring gravity in the outer solar system: the SAGAS project. Exp. Astron., 23 (2). pp. 651-687.

Marra, G; Lea, S N; Margolis, H S; Gill, P (2008) Fibre transfer of high stability microwave references with optical frequency combs. In: 2008 Lasers and Electro-optics and Quantum Electronics and Laser Science Conference, 4-9 May 2008, San Jose, CA, USA.

Margolis, H S; Lea, S N; Walton, B R; Marra, G; Reid, D T*; Gill, P (2008) Improvements to the robustness of a Ti: sapphire-based femtosecond comb at NPL. In: Proceedings of the 7th Symposium on Frequency Standards and Metrology., 5-11 October 2008, Pacific Grove, California, USA.

Marra, G; Lea, S N; Margolis, H S; Gill, P (2008) Microwave and optical frequency transfer via optical fibre. In: Proceedings of the 7th Symposium on Frequency Standards and Metrology., 5-11 October 2008, Pacific Grove, California, USA.

Webster, S A; Oxborrow, M; Pugla, S; Milo, J*; Gill, P (2008) Thermal-noise-limited optical cavity. Phys. Rev. A, 77 (3). 033847

Webster, S A; Oxborrow, M; Pugla, S; Millo, J*; Gill, P (2008) Thermal-noise-limited optical cavity. Phys. Rev. A, 77 (3). 033847

Gill, P (2008) Ultrafast optics femtosecond timing distribution. Nature Photonics, 2. pp. 711-712.

Margolis, H S; Barwood, G P; Huang, G; Klein, H A; Lea, S N; Marra, G; Tsatourian, V; Walton, B R; Gill, P (2008) An optical clock based on a single trapped 88Sr+ ion. In: Proceedings of the 7th Symposium on Frequency Standards and Metrology., 5-11 October 2008, Pacific Grove, California, USA.

Walton, B R; Margolis, H S; Tsatourian, V; Gill, P (2008) A transportable optical frequency comb based on a mode-locked fibre laser. IET Optoelectronics, 2 (5). pp. 182-187.

Brownnutt, M; Letchumanan, V; Wilpers, G; Thompson, R P; Gill, P; Sinclair, A G (2007) Controlled photoionization loading of 88Sr+ for precision ion-trap experiments. Appl. Phys. B, 87. pp. 411-415.

Christodoulia, N; Lea, S N; Marra, G; Margolis, H S; Gill, P; Leburn, C G*; Fusari, F*; Brown, C T A* (2007) Mode-locked lasers for remote intercomparison of frequency standards over optical fibre networks. In: OFMC 2007, 15-17 October 2007, NPL, UK.

Barwood, G P; Gill, P; Huang, G; Klein, H A (2007) Observation of a sub-10-Hz linewidth 88Sr+ 2S1/2-2D5/2 clock transition at 674 nm. IEEE Trans. Instrum. Meas., 56 (2). pp. 226-229.

Walton, B R; Margolis, H S; Tsatourian, V; Gill, P (2007) A transportable optical frequency comb based on a mode-locked fibre laser. In: OFMC 2007, 15-17 October 2007, NPL, UK.

Hosaka, K; Webster, S A; Stannard, A; Margolis, H S; Lea, S N; Walton, B R; Gill, P (2006) An 171Yb+ optical frequency standard at 467 nm. In: CPEM 2006 Conference on Precision Electromagnetic Measurements, 9-14 July 2006, Torino, Italy.

Hosaka, K; Webster, S A; Stannard, A; Margolis, H S; Lea, S N; Walton, B R; Gill, P (2006) An 171Yb+ optical frequency standard at 467 nm. In: CPEM 2006 Conference on Precision Electromagnetic Measurements, 9-14 July 2006, Torino, Italy.

Edwards, C S; Margolis, H S; Barwood, G P; Lea, S N; Gill, P; Rowley, W R C (2006) Development of a pair of 1.5 micron NICE ohms frequency standards. In: CPEM 2006 Conference on Precision Electromagnetic Measurements, 9-14 July 2006, Torino, Italy.

Walton, B R; Hosaka, K; Lea, S N; Margolis, H S; Gill, P (2006) Optical frequency measurements using femtosecond combs. In: Optical Frequency Combs for Space International Workshop, 2-3 October 2006, NPL, UK.

Letchumanan, V; Wilpers, G; Brownnutt, M; Gill, P; Sinclair, G (2006) Zero-point cooling and heating rate measurements of a single strontium 88 ion. In: Optical Frequency Combs for Space International Workshop, 2-3 October 2006, NPL, UK.

Brownnutt, M; Wilpers, G; Gill, P; Thompson, R C*; Sinclair, A G (2006) Zero-point cooling and heating rate measurements of a single strontium 88 ion. In: Optical Frequency Combs for Space International Workshop, 2-3 October 2006, NPL, UK.

Barwood, G P; Gill, P; Klein, H A; Huang, G; Walton, B R (2006) An optical frequency standard based on a transition in a single trapped strontium ion. In: CPEM 2006 Conference on Precision Electromagnetic Measurements, 9-14 July 2006, Torino, Italy.

Barwood, G P; Gill, P; Klein, H A; Huang, G; Walton, B R (2006) An optical frequency standard based on a transition in a single trapped strontium ion. In: CPEM 2006 Conference on Precision Electromagnetic Measurements, 9-14 July 2006, Torino, Italy.

Barwood, G P; Huang, G; Klein, H A; Margolis, H S; Lea, S N; Szymaniec, K; Chalupczak, W; Gill, P (2006) An optical frequency standard based on a transition in a single trapped strontium ion. In: Optical Frequency Combs for Space International Workshop, 2-3 October 2006, NPL, UK.

Gill, P; Margolis, H S (2005) Optical clocks. Phys. World, 18 (5). pp. 35-39.

Gill, P (2005) Optical frequency standards. Metrologia, 42 (3). S125-S137

Webster, S A; Blythe, P E; Hosaka, K; Barwood, G P; Gill, P (2004) Systematics shifts of the 467 nm electric octupole transition in 171 Yb+. NPL Report. CBTLM 31

Edwards, C S; Margolis, H S; Barwood, G P; Lea, S N; Gill, P; Huang, G; Rowley, W R C (2004) Absolute frequency measurement of a 1.5µm acetylene standard by use of a combined frequency chain and femtosecond comb. Opt. Lett., 29 (6). pp. 566-568.

Edwards, C S; Margolis, H S; Barwood, G P; Lea, S N; Gill, P; Huang, G; Rowley, W R C (2004) Absolute frequency measurements of 1.5 micron acetylene-stabilized lasers. In: Conference on Precision Electromagnetic Measurements (CPEM) 2004, 27 June - 2 July 2004, London, UK.

Margolis, H S; Huang, G; Lea, S N; Barwood, G P; Klein, H A; Gill, P (2004) Comparison of two femtosecond optical frequency combs at NPL. In: Conference on Precision Electromagnetic Measurements (CPEM) 2004, 27 June - 2 July 2004, London, UK.

Barwood, G P; Margolis, H S; Huang, G; Gill, P; Klein, H A (2004) Determination of the quadrupole frequency shift of the 2S1/2 2D5/2 transition in 88Sr+ at 674 nm. In: Conference on Precision Electromagnetic Measurements (CPEM) 2004, 27 June - 2 July 2007, London, UK.

Lea, S N; Huang, G; Margolis, H S; Gill, P (2004) Extending the range and utility of femtosecond combs. In: Conference on Precision Electromagnetic Measurements (CPEM) 2004, 27 June - 2 July 2004, London, UK.

Edwards, C S; Margolis, H S; Barwood, G P; Gill, P; Rowley, W R C (2004) Frequency measurements of 778nm rubidium two photon diode laser diodes. In: Conference on Precision Electromagnetic Measurements (CPEM) 2004, 27 June - 2 July 2004, London, UK.

Margolis, H S; Barwood, G P; Huang, G; Klein, H A; Lea, S N; Szymaniec, K; Gill, P (2004) Hertz-level measurement of the optical clock frequency in a single 88Sr+ ion. Science, 306 (5700). pp. 1355-1358.

Letchumanan, V; Gill, P; Riis, E*; Sinclair, A G (2004) Optical ramsey spectroscopy of a single trapped 88Sr+ ion. Phys. Rev. A, At. Mol. Opt. Phys., 70. 033419

Gill, P; Barwood, G P (2003) Ion trapping and laser applications to length and time metrology. In: Handbook of Laser Technology and Applications. IOP, Bristol, UK, pp. 2485-2506.

Barwood, G P; Gill, P (2003) Laser stabilisation for precision measurements. In: Handbook of Laser Technology and Applications. IOP, Bristol, UK, pp. 1393-1414.

Webster, S A; Hosaka, K; Blythe, P J; Margolis, H S; Lea, S N; Huang, G; Rowley, W R C; Gill, P (2003) Femtosecond comb measurements of the 467 nm electric octupole transition in 171Yb+. NPL Report. CBTLM 28

Margolis, H S; Huang, G; Barwood, G P; Lea, S N; Klein, H A; Rowley, W R C; Gill, P; Windeler, R S* (2003) Absolute frequency measurement of the 674 nm 88Sr+ clock transition using a femtosecond optical frequency comb. Phys. Rev. A, At. Mol. Opt. Phys., 67. 032501

Lea, S N; Rowley, W R C; Margolis, H S; Barwood, G P; Huang, G; Gill, P; Chartier, J.-M*; Windeler, R S* (2003) Absolute frequency measurements of 633 nm iodine-stabilised helium-neon lasers. Metrologia, 40. pp. 84-88.

Barwood, G P; Gao, K*; Gill, P; Huang, G; Klein, H A (2003) Observation of the hyperfine structure of the 2S1/2 - 2D5/2 674 nm optical clock transition in 87Sr+. Phys. Rev. A, At. Mol. Opt. Phys., 67. 013402

Blythe, P J; Webster, S A; Margolis, H S; Lea, S N; Huang, G; Choi, S-K; Rowley, W R C; Gill, P; Windeler, R S* (2003) Sub-kilohertz absolute frequency measurement of the 467 nm electric octupole transition in 171Yb+. Phys. Rev. A, At. Mol. Opt. Phys., 67 (2). 020501

Blythe, P J; Webster, S A; Margolis, H S; Lea, S N; Huang, G; Choi, S-K*; Rowley, W R C; Gill, P; Windeler, R S* (2003) Sub-kilohertz absolute frequency measurements of the 467 nm electric octuple transition in 171Yb+. Phys. Rev. A, At. Mol. Opt. Phys., 67. 020501

Blythe, P J; Webster, S A; Hosaka, K; Gill, P (2003) Systematic frequency shifts of the 467 nm electric octupole transition in 171Yb+. J. Phys. B, At. Mol. Phys., 36 (5). pp. 981-989.

Margolis, H S; Barwood, G P; Blythe, P J; Gill, P; Hosaka, K; Huang, G; Klein, H A; Lea, S N; Webster, S A (2003) Trapped ion optical Frequency standards and metrology. In: Digest of LEOS Summer Topical Meeting on Photonic Time/Frequency Measurement and Control, 14-16 July 2003, Vancouver, Canada.

Gill, P; Barwood, G P; Klein, H A; Huang, G; Webster, S A; Blythe, P J; Hosaka, K; Lea, S N; Margolis, H S (2003) Trapped ion optical frequency standards. Meas. Sci. Technol., 14 (8). pp. 1174-1186.

Gubin, M*; Kovalchuk, E*; Petrukhin, E*; Shelkovnikov, A*; Tyurikov, D*; Gamidov, R*; Erdogan, C*; Sahin, E*; Felder, R*; Gill, P; Lea, S N; Kramer, G*; Lipphardt, B* (2002) Absolute frequency measurements with a set of transportable He-Ne/CH4 optical frequency standards and prospects for future design and applications. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Edwards, C S; Barwood, G P; Gill, P; Rowley, W R C (2002) Development of a 778 nm rubidium two-photon diode laser frequency standard. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Lea, S N; Margolis, H S; Huang, G; Barwood, G P; Klein, H A; Blythe, P J; Webster, S A; Rowley, W R C; Gill, P; Windeler, R S* (2002) Femtosecond comb measurements of optical frequency standards at NPL. In: IEEE-LEOS 2002 15th Annual Meeting of the IEEE Lasers and Electo-Optics Society., 10-14 November 2002, Glasgow, UK.

Lea, S N; Margolis, H S; Huang, G; Rowley, W R C; Gill, P; Windeler, R S* (2002) Femtosecond optical frequency comb measurements at NPL. In: 2002 Conference on Precision Electromagnetic Measurements (CPEM), 16-21 June 2002, Ottawa, Canada.

Lea, S N; Margolis, H S; Huang, G; Rowley, W R C; Henderson, D; Barwood, G P; Klein, H A; Webster, S A; Blythe, P; Gill, P (2002) Femtosecond optical frequency comb measurements of lasers stabilised to transitions in 88Sr+, 171Yb+ and I2 at NPL. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Webster, S A; Taylor, P; Roberts, M; Barwood, G P; Gill, P (2002) Kilohertz resolution spectroscopy of the 2D1/2-2F7/2 electric octupole transition in a single 171Yb+ ion. Phys. Rev. A, At. Mol. Opt. Phys., 65 (5). 052501

Webster, S A; Taylor, P; Roberts, M; Barwood, G P; Gill, P (2002) Kilohertz resolution spectroscopy of the 2S1/2-1F7/2 electric octupole transition in a single 171Yb+ ion. Phys. Rev. A, At. Mol. Opt. Phys., 65 (5). 052501

Sinclair, A G; Wilson, M A; Letchumanan, V; Gill, P (2002) Resolved sideband cooling of a single trapped strontium ion. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Barwood, G P; Gill, P; Huang, G; Klein, H A (2002) Stability and reproducibility of an optical frequency standard based upon the 2S1/2 - 2D5/2 transition in 88Sr+. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Oxborrow, M; Webster, S A; Gill, P (2002) Stability of ND:YAG 'flywheel' lasers locked to ultra-high-finesse etalons made from either ULE or mono-crystalline-sapphire. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Webster, S A; Taylor, P; Roberts, M; Barwood, G P; Blythe, P; Gill, P (2002) A frequency standard using the 2S1/2 - 2F5/2 octupole transition in 171Yb+. In: Proceedings of the 6th Symposium on Frequency Standards and Metrology, 9-14 September 2001, University of St Andrews, Fife, Scotland, UK.

Edwards, C S; Barwood, G P; Gill, P; Bell, S A; Stevens, M; Schirmer, B*; Melling, A*; Venzke, H*; Weber, H*; Benyon, R*; Mackrodt, P*; Nielsen, J*; de Groot, M J*; Pusterla, L* (2001) Development and evaluation of a tunable diode laser absorption spectrometer for trace humidity measurements. In: TEMPMEKO 01, June 2001, Berlin, Germany.

Barwood, G P; Gao, K; Gill, P; Huang, G; Klein, H A (2001) Development of an ultra-narrow diode laser for interrogating the 674 nm 2S1/2 - 2D5/2 'clock' transition in Sr+. Proc. SPIE - Int. Soc. Opt. Eng., 4269. pp. 134-142.

Barwood, G P; Gao, K*; Gill, P; Huang, G; Klein, H A (2001) Development of optical frequency standards based upon the 2S1/2-2D5/2 transition in 88Sr+ and 87Sr+. IEEE Trans. Instrum. Meas., 50 (2). pp. 543-547.

Bell, S A; Stevens, M; Barwood, G P; Edwards, C S; Gill, P (2001) Evaluation of a tuneable diode laser absorption spectrometer against the NPL low frost-point generator. In: TEMPMEKO 01, June 2001, Berlin, Germany.

Lea, S N; Huang, G; Margolis, H S; Gill, P (2001) Femtosecond laser combs for optical measurement at NPL. In: 15th European Frequency and Time Forum., 2001.

Sinclair, A G; Wilson, M A; Gill, P (2001) Improved three-dimensional control of a single strontium ion in an endcap trap. Opt. Commun., 190. pp. 193-203.

Taylor, P; Webster, S A; Roberts, M; Rowley, W R C; Barwood, G P; Gill, P (2001) Progress towards a single ytterbium ion optical clock. Proc. SPIE - Int. Soc. Opt. Eng., 4269. pp. 155-169.

Gill, P (2001) Raising the standards (in 'Science perspective on atomic clocks'). Science, 294 (5547). pp. 1666-8.

Edwards, C S; Barwood, G P; Bell, S A; Gill, P; Stevens, M (2001) A tunable diode laser absorption spectrometer for moisture measurements in the low ppbv range. Meas. Sci. Technol., 12. pp. 1214-8.

Edwards, C S; Gill, P; Taylor, P (2000) Experimental verification of a swept-frequency laser interferometer for distance measurement. NPL Report. CBTLM 4

Margolis, H S; Lea, S N; Huang, G; Gill, P (2000) A 3 THz wide optical frequency comb for the NPL methance-to-stontium frequency chain. In: 14th EFTF Conf. Proc., 2000.

Barwood, G P; Gao, K; Gill, P; Huang, G; Klein, H A (2000) Development of optical frequency standards based upon the 2S1/2 - 2D5/2 transition in 88Sr+. In: Conference on Precision Electromagnetic Measurements (CPEM) 2000, 14-19 May 2000, Sydney, Australia.

Schirmer, B*; Venzke, H*; Melling, A*; Edwards, C S; Barwood, G P; Gill, P; Stevens, M; Benyon, R*; Mackrodt, P* (2000) High precision trace humidity measurements with a fibre-coupled diode laser absorption spectrometer at atmospheric pressure. Meas. Sci. Technol., 11. pp. 382-391.

Edwards, C S; Barwood, G P; Gill, P; Stevens, M; Schirmer, B*; Benyon, R*; Mackrodt, P* (2000) An IR tunable diode laser absorption spectrometer for trace humidity measurements at atmospheric pressure. IEEE Lasers and Electro-Optics Society Newsletter, 14 (5). pp. 13-14.

Roberts, M; Taylor, P; Barwood, G P; Rowley, W R C; Gill, P (2000) Observation of the 2S1/2-2F7/2 electric octupole transition in a single 171Yb+ ion. Phys. Rev. A, At. Mol. Opt. Phys., 62 (2). 020501(R)

Gill, P (2000) Optical Clocks coming of age. Nature, 407 (6804). pp. 579-580.

Klein, H A; Barwood, G P; Gill, P; Huang, G (2000) Single trapped ions for optical frequency standards. Phys. Scr. Vol. T, 86. pp. 33-37.

Gill, P; Huang, G; Lea, S N; Margolis, H S (2000) An optical frequency chain for absolute frequency measurement of the 445 THz strontium trapped ion frequency standard. In: Conference on Precision Electromagnetic Measurements (CPEM) 2000, 14-19 May 2000, Sydney, Australia.

Roberts, M; Taylor, P; Gill, P (1999) Laser linewidth at the sub-Hertz level. NPL Report. CLM 8

Edwards, C S; Barwood, G P; Gill, P; Rowley, W R C (1999) A 633nm iodine-stabilised diode laser frequency standard. Metrologia, 36 (1). pp. 41-45.

Edwards, C S; Barwood, G P; Gill, P; Schirmer, B*; Venzke, H*; Melling, A* (1999) Development of an IR tunable diode laser absorption spectrometer for trace humidity measurements at atmospheric pressure. Appl. Opt., 38 (21). pp. 4699-4704.

Barwood, G P; Gill, P; Huang, G; Klein, H A (1999) Development of an optical frequency standard based upon the 2S1/2-2D5/2 transition in Sr+. In: 13th EFTF/ 1999 IEEE FCS Conference Proceedings, 1999.

Macfarlane, G M; Barwood, G P; Rowley, W R C; Gill, P (1999) Interfeometric frequency measurements of an iodine stabilised Nd:YAG laser. IEEE Trans. Instrum. Meas., 48 (2). pp. 600-603.

Roberts, M; Taylor, P; Gateva-Kostova, S V*; Clarke, R B M*; Rowley, W R C; Gill, P (1999) Measurement of the 2S1/2-2D5/2 clock transition in a single 171Yb+ ion. Phys. Rev. A, At. Mol. Opt. Phys., 60 (4). pp. 2867-2872.

Taylor, P; Roberts, M; Macfarlane, G M; Barwood, G P; Rowley, W R C; Gill, P (1999) Measurement of the infrared 2F7/2-2D5/2 transition in a single 171Yb+ ion. Phys. Rev. A, At. Mol. Opt. Phys., 60 (4). pp. 2829-2833.

Lea, S N; Huang, G; Margolis, H S; Macfarlane, G M; Taylor, P; Gill, P (1999) Optical frequency synthesis in the near IR with application to trapped ion standards. In: Proc. 1999 Joint Meeting of the European Frequency and Time Forum and the IEEE International Frequency Control Symp., 13-16 April 1999, Besancon, France.

Lea, S N; Macfarlane, G M; Gill, P (1999) Progress towards an optical frequency chain at NPL. IEEE Trans. Instrum. Meas., 48 (2). pp. 578-582.

Roberts, M; Taylor, P; Gill, P (1999) Single ion spectroscopy of ytterbium. In: 13th EFTF/ 1999 IEEE FCS Conference Proceedings, 1999.

Barwood, G P; Huang, G; Klein, H A; Gill, P; Clarke, R B M* (1999) Sub-kHz comparison of the single-ion optical-clock 2S1/2 - 2D5/2 transition in two 88Sr+ traps. Phys. Rev. A, At. Mol. Opt. Phys., 59. R3178-81

Taylor, P; Roberts, M; Barwood, G P; Gill, P (1998) Combined optical infrared single ion frequency standard. Opt. Lett., 23 (4). pp. 298-300.

Taylor, P; Roberts, M; Barwood, G P; Gill, P (1998) Combined optical-infrared single ion frequency standard. In: Proc. 1998 CPEM Digest, July 1998, Washington, DC, USA.

Taylor, P; Roberts, M; Barwood, G P; Gill, P (1998) Combined optical-infrared single ion-frequency standard. In: CPEM '98 Conference on Precision Electromagnetic Measurements Conference Digest, 6-10 July 2003, Washington DC, USA.

Barwood, G P; Gill, P; Rowley, W R C (1998) High accuracy length metrology using multiple-stage swept-frequency interferometry with laser diodes. Meas. Sci. Technol., 9 (7). pp. 1036-41.

Macfarlane, G M; Barwood, G P; Rowley, W R C; Gill, P (1998) Interferometric frequency measurements of an iodine stabilised Nd:YAG laser. In: Proc. 1998 CPEM Digest, July 1998, Washington, DC, USA.

Macfarlane, G M; Barwood, G P; Rowley, W R C; Gill, P (1998) Interferometric frequency measurements of an iodine stabilised Nd:YAG laser. In: CPEM '98 Conference on Precision Electromagnetic Measurements Conference Digest, 6-10 July 2003, Washington DC, USA.

Lea, S N; Macfarlane, G M; Huang, G; Gill, P (1998) Progress towards an optical frequency chain at NPL. In: CPEM '98 Conference on Precision Electromagnetic Measurements Conference Digest, 6-10 July 2003, Washington DC, USA.

Barwood, G P; Gill, P; Klein, H A; Rowley, W R C (1998) Sub-kHz "clock" transition linewidths in a cold trapped 88Sr+ ion in low magnetic fields using 1092-nm polarisation switching. Opt. Commun., 151 (1-3). pp. 50-5.

Clarke, R B W*; Riis, E*; Barwood, G P; Gill, P; Huang, G; Klein, H A (1998) A sideband-injection locked extended cavity diode laser for interrogating cold trapped strontium ions. Opt. Commun., 158 (1-6). pp. 36-40.

Gill, P (1997) Applications of laser cooled trapped ions. In: Proc. URSI General Assembly, 29 August 1997, Lille, France.

Barwood, G P; Gill, P; Klein, H A; Rowley, W R C (1997) Clearly resolved secular sidebands on the 2S1/2-2D5/2 674nm clock transition in a single trapped Sr+ ion and prospects for trapped ion frequency standards. IEEE Trans. Instrum. Meas., 46 (2). pp. 133-136.

Taylor, P; Roberts, M; Gateva-Kostova, S V*; Clarke, R B W*; Barwood, G P; Rowley, W R C; Gill, P (1997) Investigation of the 2S1/2-2D5/2 clock transition in a single ytterbium ion. Phys. Rev. A, 56. p. 2699.

Roberts, M; Taylor, P; Barwood, G P; Gill, P; Klein, H A; Rowley, W R C (1997) Observation of an electric octupole transition in a single Ion. Phys. Rev. Lett., 78 (10). pp. 1876-1879.

Barwood, G P; Gill, P; Huang, G; Klein, H A; Rowley, W R C (1997) Single Sr+ Ion spectroscopy with a sub-kHz linewidth diode probe laser. In: 13th International Conference on Laser Spectroscopy, June 1997, Hangzhou, China.

Gill, P; Klein, H A; Roberts, M; Rowley, W R C; Taylor, P (1996) Absolute measurement of the 2S1/2 - 2D5/2 411nm interval, and the search for the 2S1/2 - 2F7/2 467nm transition in laser-cooled trapped 172Yb+. In: Proc. Fifth symposium on Frequency Standards and Metrology, 1996, Singapore.

Edwards, C S; Barwood, G P; Gill, P; Rodriguez-Llorente, F*; Rowley, W R C (1996) Frequency-stabilised diode lasers in the visible region using Doppler-free iodine spectra. Opt. Commun.,, 132. pp. 94-100.

Barwood, G P; Gill, P; Klein, H A; Rowley, W R C (1996) Observation of fluorescence from cold trapped Sr ions in a near-zero magnetic field and 674nm probe laser development. In: Proc. Fifth symposium of Frequency Standards and Metrology, 1996, Singapore.

Lea, S N; Gill, P (1996) Proposed infra-red to visible frequency chain at NPL. In: Proc. Fifth symposium on Frequency Standards and Metrology, 1996, Singapore.

Edwards, C S; Barwood, G P; Gill, P; Rodriguez-Llorente, F*; Rowley, W R C (1996) Stability measurement of 637nm extended cavity diode lasers stabilised to Doppler-free iodine spectra. In: Proc. Fifth symposium on Frequency Standards and Metrology, 1996, Singapore.

Edwards, C S; Barwood, G P; Gill, P; Rowley, W R C (1995) Absolute frequency stabilisation of a 637nm laser diode using Doppler-free I2 spectra. Electron. Lett., 31 (10). pp. 796-797.

Gill, P; Klein, H A; Levick, A P; Rowley, W R C; Taylor, P (1995) Measurement of the 2S1/2 - 2D5/2 411 nm interval in laser-cooled 172Yb+ ions. Phys. Rev. A, At. Mol. Opt. Phys., 52. R909-912

Amos, B*; Gill, P (1995) Optical tweezers. Meas. Sci. Technol., 6. p. 248.

Barwood, G P; Edwards, C S; Gill, P; Huang, G; Klein, H A; Rowley, W R C (1995) Precision interferometric frequency measurement of the 674nm 2S1/2 - 2D5/2 transition in a single cold Sr+ ion. IEEE Trans. Instrum. Meas., 44 (2). pp. 117-119.

Barwood, G P; Gill, P; Huang, G; Klein, H A (1995) Studies of trapped strontium ions in low magnetic fields. Appl. Phys. B, Laser Opt., 61 (4). p. 385.

Barwood, G P; Edwards, C S; Gill, P; Klein, H A; Rowley, W R C (1994) Laser cooling and probing of a trapped strontium ion using all-solid-state lasers. AIP Conf. Proc., 290. pp. 35-37.

Edwards, C S; Gill, P; Klein, H A; Levick, A P; Rowley, W R C (1994) Laser-cooling effects in few-ion clouds of Yb/sup +/. Appl. Phys. B, Laser and Optics, B59 (2). 179 - 185

Edwards, C S; Gill, P; Klein, H A; Levick, A P; Rowley, W R C (1994) Precision measurement of the 2S1/2(2 sps-1/2 sbs) - 2D5/2(2 sps-5/2 sbs) 411 nm transition in laser-cooled 172Yb+ (172 & + in sps) ions. In: 5th European Quantum Electronics Conference, Technical Digest, 53, 1994, Amsterdam, Holland.

Gill, P; Klein, H A; Levick, A P; Roberts, M; Rowley, W R C; Taylor, P (1994) A search for the 2S1/2 (2 sps - 1/2sbs) - 2F7/2 (2 sps -7/2sbs) 467 nm transition in laser cooled 172Yb+. (172 & + sps). In: 14th International Conference Digest on Atomic Physics, 1994, Boulder, Colorado, USA.

Barwood, G P; Edwards, C S; Gill, P; Klein, H A; Rowley, W R C (1993) Development of diode and fibre laser sources for a Sr+ trapped ion optical frequency standard. Proc. SPIE - Int. Soc. Opt. Eng., 1837. pp. 271-7.

Barwood, G P; Gill, P; Rowley, W R C (1993) Laser diodes for length determination using swept-frequency interferometry. Meas. Sci. Technol., 4 (9). pp. 988-994.

Gill, P (1993) Laser interferometry for precision engineering. In: Optical Methods in Engineering Metrology. Chapman & Hall, London, pp. 153-177.

Barwood, G P; Edwards, C S; Gill, P; Klein, H A; Rowley, W R C (1993) Observation of the 5s2S1/2-4d2D5/2 transition in a single laser-cooled trapped Sr+ ion using an all-solid-state system of lasers. Opt. Lett., 18 (9). pp. 732-734.

Barwood, G P; Gill, P; Rowley, W R C (1993) Optically narrowed Rb-stabilised GaAlAs diode laser frequency standards with 1.5x10-10 absolute accuracy. Proc. SPIE - Int. Soc. Opt. Eng., 1837. pp. 262-270.