Single-frequency Laser Output Research Articles

61 W single frequency laser output at 1645 nm from a resonantly pumped Er:YAG nonplanar ring oscillator

A monolithic 1645 nm Er:YAG nonplanar ring oscillator (NPRO) resonantly pumped by a 1532 nm fiber laser is demonstrated. For reducing the energy-transfer upconversion effect, a 0.5% doped Er:YAG nonplanar crystal was used. An up to 6.1 W single frequency laser output at 1645 nm was obtained, with a slope efficiency of 55.2% and an optical efficiency of 48.0%. The linewidth of the Er:YAG NPRO was 14.4 kHz.

7.5 W Nd:GdVO4环形腔单频激光器

A Nd:GdVO4 crystal is end-pumped by a fiber-coupled laser diode(FCLD), and high power of single-frequency laser output is achieved. The four-mirror bow-tie ring cavity with a Faraday rotator and a half wave plate is applied to eliminate the spatial hole-burning effect. A solid etalon is inserted into the cavity to obtain single-frequency1063 nm output of the narrow line width. The maximum output is7.57 W and the optical-optical conversion efficiency is41.8% with18.10 W of the incident power.

Power Scaling of Single-Frequency Hybrid Brillouin/Ytterbium Fiber Lasers

A coupled-wave rate-equation model, including multiple-order stimulated Brillouin scattering (SBS), is used to study power scaling of hybrid Brillouin/ytterbium fiber lasers. To validate the model, a single-frequency, Brillouin/ytterbium fiber laser was built with a laser output of 40 mW and an optical signal-to-noise ratio greater than 50 dB. The numerical model simulation agrees with the measurements in both fully and partially injection locked regimes. To scale up the laser's output power, a dual-clad architecture is proposed. In this new configuration, the active Yb-doped fiber provides the nonlinear SBS gain as well as the gain resulting from the excited Yb ions. Numerical modeling including three Stokes orders shows that over 5 W of single-frequency laser output can be achieved with a side-mode suppression ratio (SMSR) of greater than 80 dB. Beyond this power, multi-order SBS affects the laser efficiency and SMSR.

Passively Q-switched laser with single longitudinal mode based on the frequency selection of grating and F-P etalon in twisted-mode folded cavity

A passively Q-switched side-pumped laser with folded resonator is specially constructed for singlelongitudinal-mode smooth pulse output. Nd:YAG is chosen as the laser active medium and Crlsupg4+l/supg:YAG as the saturable absorber medium. Additionally, the method of frequency selection by grating with 1200 line/mm and Fabry-Perot (F-P) etalon is used in the twisted-mode cavity. The single-frequency smooth pulses are produced with 10-Hz repetition rate, 20-ns pulse width, and 1.064-\mu m wavelength. The probability of single-frequency laser output measured is over 99% by using the methods of Fourier analysis and F-P etalon multiple-beam interferometry at the threshold voltage. The measured near-field and far-field angles of divergence are 1.442 and 1.315 mrad, respectively. The values of Mlsupg2l/supg are 1.32 and 1.31 separately with the knife-edge method. Single pulse at 1.064 \mu m with the energy of 8.8 mJ is achieved in TEMlsubg00l/subg mode.

Phase laser intracavity spectroscopy

A method of metallic thin-film surface conductivity monitoring is proposed and realized. The method is based on the dependency of the single-frequency laser output on the position of a thin absorbing film in the linear cavity. The real and imaginary parts of the surface conductivity of cobalt and chromium thin (~10 nm) films were measured for radiation with wavelength of about 1 µm.

Highly efficient hybrid fiber taper coupled microsphere laser

A novel hybrid fiber taper is proposed and demonstrated as the coupler in a microsphere laser system. The pump wave and the laser emission, respectively, are more efficiently coupled to and from the sphere modes with this taper structure. A 980-nm pumped erbium-ytterbium codoped phosphate microsphere laser is demonstrated in the 1550-nm band. As much as 112microW of single-frequency laser output power was measured, with a differential quantum efficiency of 12%.

Semimonolithic Nd:YAG ring resonator for generating cw single-frequency output at 106 μm

We report 2.1 W of unidirectional single-frequency laser output from a novel Nd:YAG ring laser longitudinally pumped by a laser diode bar. The resonator requires only a single discrete optic and magnet, in addition to the laser medium, for stable multiwatt single-frequency operation. Undoped YAG is diffusion bonded to the Nd:YAG laser crystal at the pump face to eliminate residual spatial hole burning and improve thermal conductivity. This new laser design can be scaled to higher powers through more facile diode access and is useful for cw intracavity doubling.

Single frequency TE CO 2 lasers with a simple structure

Single frequency laser output has been obtained for the first time from a transverse excitation (TE)CO 2 laser by shortening the cavity length and decreasing the total gas pressure appropriately.