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Nomura J, Hirosawa K, Yanagisawa T, Ohata N, Imamura S, Sakaizawa D, Tomii N. Single-frequency 45-mJ pulses from a MOPA system using an Er,Yb:glass planar waveguide amplifier and a large mode area Er-doped fiber amplifier. OPTICS LETTERS 2023; 48:1758-1761. [PMID: 37221759 DOI: 10.1364/ol.485519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/23/2023] [Indexed: 05/25/2023]
Abstract
We demonstrate a master oscillator power amplifier (MOPA) system that emits single-frequency high-energy optical pulses at 1540 nm using an Er,Yb:glass planar waveguide amplifier and a large mode area Er-doped fiber amplifier. A double under-cladding and a 50-µm-thick core structure are employed for the planar waveguide amplifier to increase the output energy without degrading the beam quality. A pulse energy of 45.2 mJ with a peak power of 27 kW is generated at a pulse repetition rate of 150 Hz with a pulse duration of 1.7 µs. Moreover, the beam quality factor M2 of the output beam is 1.84 at the highest pulse energy thanks to its waveguide structure.
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Zeyen M, Affolter L, Ahmed MA, Graf T, Kara O, Kirch K, Marszalek M, Nez F, Ouf A, Pohl R, Rajamohanan S, Yzombard P, Antognini A, Schuhmann K. Pound-Drever-Hall locking scheme free from Trojan operating points. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:013001. [PMID: 36725577 DOI: 10.1063/5.0130508] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
The Pound-Drever-Hall (PDH) technique is a popular method for stabilizing the frequency of a laser to a stable optical resonator or, vice versa, the length of a resonator to the frequency of a stable laser. We propose a refinement of the technique yielding an "infinite" dynamic (capture) range so that a resonator is correctly locked to the seed frequency, even after large perturbations. The stable but off-resonant lock points (also called Trojan operating points), present in conventional PDH error signals, are removed by phase modulating the seed laser at a frequency corresponding to half the free spectral range of the resonator. We verify the robustness of our scheme experimentally by realizing an injection-seeded Yb:YAG thin-disk laser. We also give an analytical formulation of the PDH error signal for arbitrary modulation frequencies and discuss the parameter range for which our PDH locking scheme guarantees correct locking. Our scheme is simple as it does not require additional electronics apart from the standard PDH setup and is particularly suited to realize injection-seeded lasers and injection-seeded optical parametric oscillators.
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Affiliation(s)
- Manuel Zeyen
- Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland
| | - Lukas Affolter
- Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland
| | - Marwan Abdou Ahmed
- Institut für Strahlwerkzeuge, Universität Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Deutschland
| | - Thomas Graf
- Institut für Strahlwerkzeuge, Universität Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Deutschland
| | - Oguzhan Kara
- Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland
| | - Klaus Kirch
- Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland
| | | | - François Nez
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-Université PSL, Collège de France, 75252 Paris Cedex 05, France
| | - Ahmed Ouf
- QUANTUM, Institute of Physics, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Randolf Pohl
- QUANTUM, Institute of Physics, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Siddharth Rajamohanan
- QUANTUM, Institute of Physics, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Pauline Yzombard
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-Université PSL, Collège de France, 75252 Paris Cedex 05, France
| | - Aldo Antognini
- Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland
| | - Karsten Schuhmann
- Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland
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