Abgrall, M; Chupin, B; Uhrich, P; Lorini, L; Le Targat, R; Pointard, B; Lodewuck, J; Tunesi, J; Tran, D B A; Parsons, A O; Tofful, A; Robertson, B I; Johnson, M Y H; Feng, C-H; Schioppo, M; Curtis, E A; Hill, I R; Godun, R M; Margolis, H S (2024) Optically steered time scale generation at OP and NPL and remote comparisons. Journal of Physics: Conference Series, 2889. 012024

Margolis, H S; Godun, R M; Huntemann, N; le Targat, R; Pizzocaro, M; Zawada, M; Abgrall, M; Akamatsu, D; Alvarez Martinez, H; Amy-Klein, A; Andia, M; Benkler, E; Bhatt, N M; Bilicki, S; Bize, S; Bober, M; Calonico, D; Cambier, V; Cantin, E; Chardonnet, C; Cifuentes Marin, M; Clivati, C; Condio, S; Curtis, E A; Czubla, A; Dolezal, M; Doescher, S; Dunst, P; Feng, C-H; Filzinger, M; Folman, R; Fordell, T; Formichella, V; Foucault, Y; Galleani, L; Goti, I; Groswasser, D; Gruszczynski, M; Guo, C; Hanhijarvi, K J; Hausser, H N; Hill, I R; Hosaka, K; Johnson, M Y H; Keller, J; Klose, J; Kobayahi, T; Koke, S; Kovacic, D; Kren, P; Kuhl, A; Ledzinski, A; Lemanski, D; Levi, F; Lindvall, T; Lisdat, C; Liu, H; Lodewyck, J; Lopez, O; Lorini, L; Lours, M; Masika, P; Mazouth-Laurol, M; Mehlstaubler, T E; Moreno, W; Morzynski, A; Naroznik, M; Nawrocki, J; Nishiyama, A; Nogas, P; Nordmann, T; Parsons, A O; Pointard, B; Pottie, P E; Risaro, M; Robertson, B I; Romero Gonzalez, J; Schioppo, M; Sesia, I; Shang, H; Signorile, G; Stahl, K; Steinel, M; Sterr, U; Suavez Ramirezi, J; Tofful, A; Tonnes, M; Tran, A; Tunesi, J; Wallin, A E; Waterholter, T; Zarei, M; Zyskind, C (2024) Robust Optical Clocks for International Timescales (ROCIT). Journal of Physics: Conference Series, 2889. 012022

Jones, D J M; Aikomo, M; Ashford, S; Ashkhasi, A; Davis, J A; Devine, B; Eglin, B; Everett, S B; Foot, R; Galbraith, D; Hendricks, R J; Khatry, K; Langham, C; Lewis, R; Newton-Griffiths, J; Owen, H; Shemar, S L; Sheppard, A; Smyth, C; Szymaniec, K; Walby, S; Weston, D F M; Whale, J; Whibberley, P B; Wilson, A; Wilson, C; Margolis, H S (2024) A new resilient time and frequency infrastructure for UTC(NPL). Journal of Physics: Conference Series, 2889. 012025

Tofful, A; Baynham, C F A; Curtis, A; Parsons, A O; Robertson, B I; Schioppo, M; Tunesi, J; Margolis, H S; Hendricks, R J; Whale, J; Thompson, R C; Godum, R M (2024) 171Yb+ optical clock with 2.2 × 10−18 systematic uncertainty and absolute frequency measurements. Metrologia, 61 (4). 045001

Margolis, H S; Panfilo, G; Petit, G; Oates, C; Ido, T; Bize, S (2024) The CIPM list “Recommended values of standard frequencies”: 2021 update. Metrologia, 61 (3). 035005

Dimarcq, N; Gertsvolf, M; Mileti, G; Bize, S; Oates, C W; Peik, E; Calonico, D; Ido, T; Tavella, P; Meynadier, F; Petit, G; Panfilo, G; Bartholomew, J; Defraigne, P; Donley, E A; Hedekvist, P O; Sesia, I; Wouters, M; Dube, P; Fang, F; Levi, F; Lodenyck, J; Margolis, H S; Newell, D; Slyusarev, S; Weyers, S; Uzan, J-P; Yasuda, M; Yu, D-H; Rieck, C; Schnatz, H; Hanado, Y; Fujieda, M; Pottie, P-E; Hanssen, J; Malimon, A; Ashby, N (2024) Roadmap towards the redefinition of the second. Metrologia, 61 (1). 012001

Sherril, N; Parsons, A O; Baynham, C F A; Bowden, W; Curtis, E A; Hendricks, R; Hill, I R; Hobson, R; Margolis, H S; Robertson, B I; Schioppo, M; Szymaniec, K; Tofful, A; Tunesi, J; Godun, R M; Calmet, X (2023) Analysis of atomic-clock data to constrain variations of fundamental constants. New Journal of Physics, 25. 093012

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

Schioppo, M; Kronjaeger, J; Silva, A; Ilieva, R; Paterson, J W; Baynham, C F A; Bowden, W; Hill, I R; Hobson, R; Vianello, A; Dovale- Alvarez, M; Williams, R A; Marra, G; Margolis, H S; Amy-Klein, A; Lopez, O; Cantin, E; Alvarez-Martinez, H; Le Target, R; Pottie, P E; Quintin, N; Legero, T; Hafner, S; Sterr, U; Schwarz, R; Dorscher, S; Lisdat, C; Koke, S; Kuhl, A; Waterholter, T; Benkler, E; Grosche, G (2022) Comparing ultrastable lasers at 7 x 10(-17) fractional frequency instability through a 2220 km optical fibre network. Nature Communications, 13 (1). 212

Barontini, G; Boyer, V; Calmet, X; Fitch, N J; Forgan, E M; Godun, R M; Goldwin, J; Guarrera, V; Hill, I R; Jeong, M; Keller, M; Kuipers, F; Margolis, H S; Newman, P; Prokhorov, L; Rodewald, J; Sauer, B E; Schioppo, M; Sherrill, N; Tarbutt, M R; Vecchio, A; Worm, S (2021) QSNET, a network of clocks for measuring the stability of fundamental constants. Proceedings of the SPIE, 11881. 118810K

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

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

Margolis, H S; Denker, H; Voigt, C; Timmen, L; Grotti, J; Koller, S; Vogt, S; Häfner, S; Sterr, U; Lisdat, C; Rolland, A; Baynes, F N; Zampaolo, M; Thoumany, P; Pizzocaro, M; Rauf, B; Bregolin, F; Tampellini, A; Barbieri, P; Zucco, M; Costanzo, G A; Clivati, C; Levi, F; Calonico, D (2019) Optical Atomic Clocks: From International Timekeeping to Gravity Potential Measurement. In: 2019 Conference on Lasers and Electro-Optics (CLEO), 5-10 May 2019, San Jose, CA, USA.

Grotti, J; Koller, S; Vogt, S; Häfner, S; Sterr, U; Lisdat, C; Denker, H; Voigt, C; Timmen, L; Rolland, A; Baynes, F N; Margolis, H S; Zampaolo, M; Thoumany, P; Pizzocaro, M; Rauf, B; Bregolin, F; Tampellini, A; Barbieri, P; Zucco, M; Costanzo, G A; Clivati, C; Levi, F; Calonico, D (2018) Geodesy and metrology with a transportable optical clock. Nature Physics, 14 (5). pp. 437-441. ISSN 1745-2473

Denker, H; Timmen, L; Voigt, C; Weyers, S; Peik, E; Margolis, H S; Delva, P; Wolf, P; Petit, G (2018) Geodetic methods to determine the relativistic redshift at the level of 10^-18 in the context of international timescales: a review and practical results. Journal of Geodesy, 92 (5). pp. 487-516. ISSN 0949-7714

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.

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

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

Lessing, M; Margolis, H S; Brown, C T A*; Marra, G (2017) Frequency comb-based time transfer over a 159 km long fiber network. Appl. Phys. Lett., 110 (22). 221101

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

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.

Lessing, M*; Margolis, H S; Brown, C T A*; Marra, G (2015) Simultaneous time and frequency transfer over a 158-km-long fiber network using a mode-locked laser. In: 2015 Conference on Lasers and Electro-Optics (CLEO), 10-15 May 2015, San Jose, CA, USA.

Matus, M*; Edwards, C; Margolis, H S; Piree, H*; Sahin, E*; Birlikseven, C*; Robertsson, L* (2015) The CCL-K11 ongoing key comparison. Final report for the year 2013. Metrologia, 52 (1A). 04006.

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.

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

Margolis, H S (2014) Optical atomic clocks in ion traps. pp. 261-274.

Margolis, H S (2014) Timekeepers of the future. Nature Physics, 10 (2). pp. 82-83.

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.

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.

Margolis, H S (2013) How big is the proton? Science, 339 (6118). pp. 405-406.

Margolis, H S (2013) Opportunities knock with a more stable optical clock. Science, 341 (6151). pp. 1185-1186.

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.

Marra, G; Margolis, H S; Richardson, D J* (2012) Dissemination of an optical frequency comb over fiber with 3 x 10(-18) fractional accuracy. In: 2012 Conference on Lasers and Electro-optics (CLEO), 6-11 May 2012, San Jose, CA, USA.

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

Marra, G; Margolis, H S; Richardson, D J* (2012) Dissemination of an optical frequency comb over fiber with 3 x 10(-18) fractional accuracy. Opt. Express, 20 (2). pp. 1775-1782.

Margolis, H S (2012) Spectroscopic applications of femtosecond optical frequency combs. Chem. Soc. Rev., 41 (15). pp. 5174-5184.

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.

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.

Margolis, H S (2010) Optical frequency standards and clocks. Contemp. Phys., 51 (1). pp. 37-58.

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.

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

Margolis, H S (2009) Frequency metrology and clocks. J. Phys. B, At. Mol. Phys., 42 (15). 154017

Margolis, H S (2009) Lattice clocks embrace ytterbium. Nature Photonics, 3 (10). pp. 557-558.

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.

Margolis, H S (2009) Trapped ion optical clocks. Eur. Phys. J. Special Topics, 172. pp. 97-107.

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.

Flowers, J L; Baird, P E G*; Evans, A*; Klein, H A; Langham, C D; Mairiniac, L*; Margolis, H S; Walton, B R (2008) Optical spectroscopy of atomic hydrogen for an improved determination of the Rydberg constant. In: Proceedings of the 7th Symposium on Frequency Standards and Metrology., 5-11 October 2008, Pacific Grove, California, USA.

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.

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.

Margolis, H S (2007) Moving metrology. Nature Photonics, 1 (5). pp. 258-259.

Flowers, J L; Baird, P E G*; Bougueroua, L; Klein, H A; Margolis, H S (2007) The NPL Rydberg constant experiment. IEEE Trans. Instrum. Meas., 56 (2). pp. 331-335.

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.

Flowers, J L; Baird, P E G*; Bougueroua, L; Klein, H A; Margolis, H S (2006) The NPL Rydberg constant experiment. 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.

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.

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.

Flowers, J L; Klein, H A; Margolis, H S; Reed, R P (2004) Precision spectroscopy of metastable atomic hydrogen: towards an improved determination of the Rydburg constant. In: Conference on Precision Electromagnetic Measurements (CPEM) 2004, 27 June - 2 July 2004, London, UK.

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.

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

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.

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.

Flowers, J L; Klein, H A; Knight, D J E; Margolis, H S (2001) Hydrogenic systems for calculable frequency standards: status and options. NPL Report. CBTLM 11

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.

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.

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.

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.