A Review of the High-Power All-Solid-State Single-Frequency Continuous-Wave Laser

Abstract

High-power all-solid-state single-frequency continuous-wave (CW) lasers have been applied in basic research such as atomic physics, precision measurement, radar and laser guidance, as well as defense and military fields owing to their intrinsic advantages of high beam quality, low noise, narrow linewidth, and high coherence. With the rapid developments of sciences and technologies, the traditional single-frequency lasers cannot meet the development needs of emerging science and technology such as quantum technology, quantum measurement and quantum optics. After long-term efforts and technical research, a novel theory and technology was proposed and developed for improving the whole performance of high-power all-solid-state single-frequency CW lasers, which was implemented by actively introducing a nonlinear optical loss and controlling the stimulated emission rate (SER) in the laser resonator. As a result, the output power, power and frequency stabilities, tuning range and intensity noise of the single-frequency lasers were effectively enhanced.

Performance Improvement of Single-Frequency CW Laser Using a Temperature Controller Based on Machine Learning

“…All-solid-state continuous wave (CW) single-frequency lasers have been applied in quantum optics and quantum information [ 1 , 2 ], precision measurement [ 3 ], optical holography [ 4 ], optical storage [ 5 ], cutting [ 6 ], welding [ 7 , 8 , 9 ], sensing [ 10 , 11 ] and so on, owing to their intrinsic advantages of compact structure, high stability, low intensity noise and high beam quality [ 12 , 13 ]; however, in order to attain a stable all-solid-state single-frequency CW laser with high output power, the temperatures of the pump source and gain crystal as well as nonlinear crystal must be precisely controlled in addition to the design of a unidirectional resonator to eliminate the spatial hole burning effect [ 14 ]. Especially for the gain crystal, in the process of laser emission, a lot of waste heat is generated due to quantum defect, energy transfer upconversion (ETU), excited state absorption (ESA) and cross relaxation (CR), and dissipates within the host lattice, which can change the operating temperature of the gain crystal and further induce the thermal lens effect, thermal astigmatism and so on [ 15 , 16 ].…”

Recent progress in continuously tunable low-noise all-solid-state single-frequency continuous-wave laser based on intracavity locked etalon

“…On the other hand, the broadband mode-hop-free continuous frequency tuning is also essential for a high-power single-frequency CW laser to guarantee its long-term stable single-logitudinal-mode (SLM) operation and enhance its adaptation to the application environment. Due to the thermal effect is extremely severe and the mode competition is fierce in the high-power single-frequency CW laser, in the same time its frequency will drift with the temperature fluctuation and air flow of the ambient environment under long-term operation, the multi-longitudinal-mode (MLM) oscillation or mode-hopping of the laser is very easy to happen [8]. Nevertheless, once the broadband continuous frequency tuning capability is equipped in a high-power single-frequency CW laser, the same one oscillating laser mode is always selected within the broadband tuning range and the other non-lasing modes are suppressed, thus ensuring that the oscillating laser mode remains oscillating in the tuning range and the mode-hop is suppressed.…”

Single-frequency lasing in a CW TEМ00 Nd:YVO4 disk laser with an M-type degenerate cavity and three-beam pumping

“…Continuous-wave (CW) solid-state lasers with high beam quality and narrow linewidth (⩽10 −2 cm −1 ) are in great demand in various fields of science and technology such as LIDARs, laser cooling, holography, nonlinear optics, and others. At the moment, there are many approaches to obtain single-frequency lasing with narrow linewidth in solidstate lasers: the use of ring resonators [1,2]; application of wavelength selectors such as Fabry-Pérot interferometers (IFPs) and diffraction gratings [1,3,4]; and the application of nonlinear crystals [1,2,5]. These methods allow one to obtain single-frequency lasing with spectral bandwidth up to 1 kHz at output power up to tens of watts.…”