Dual-polarization modes and self-heterodyne noise in a single-frequency 2.1-microm microchip Ho,Tm:YAG laser

Diode-end-pumped continuously tunable single frequency Tm, Ho:LLF laser at 2.06 μm

We report on a laser diode-end-pumped continuously tunable single frequency Tm, Ho:LLF laser near room temperature. For transmission of 5%, the maximum single frequency output power of 221 mW at 2064.4 nm was obtained by using two uncoated etalons. The single frequency Tm, Ho:LLF laser operated on the fundamental transverse mode with an M2 factor of 1.13, and the output frequency could be tuned continuously near 1.5 GHz by angle tuning only of the 1 mm thick etalon. Furthermore, the influence of output coupler transmission on the laser performance was also investigated. The single frequency laser can be used as a seed laser for coherent Doppler lidar and differential absorption lidar systems.

Experimental Observations of Dual-Polarization Oscillations in Laser-Diode-Pumped Wide-Aperture Thin-Slice Nd:GdVO(4) Lasers

Dual-polarization oscillations (DPO) on different transitions have been observed for the first time in a mirror-coated thin-slice Nd:GdVO(4) laser possessing a large fluorescence anisotropy with laser-diode (LD) pumping. Oscillation spectra, input-output characteristics, pump-dependent pattern formations and noise power spectra are studied experimentally. Simultaneous oscillations of orthogonally-polarized different (higher-order) transverse modes and the resultant violation of inherent antiphase dynamics in multimode lasers have been demonstrated. The experimental results have been explained in terms of the reduced three-dimensional cross-saturation of population inversions among orthogonally-polarized modes peculiar to LD-pumped wide-aperture anisotropic lasers, in which a pumped area is larger than a lasing beam diameter.

Dual-polarization microchip laser at 1.53 microm

Two-frequency operation of a composite Er,Yb:glass-LiTaO3 monolithic microlaser is demonstrated at 1.53 microm. The thermo-optic effect of the intracavity birefringent crystal makes it possible to control the wavelengths of the two orthogonal linearly polarized eigenstates. It provides a tunable beat note from 0 to 60 GHz. Direct evaluation of the Lamb-type coupling constant C between the two eigenstates is obtained from a single intensity noise spectrum measurement, yielding values from 0.33 to 0.86, depending on transverse and axial distributions of the eigenstates. Applications to radar and telecommunication systems are discussed.