Diode-pumped Nd:YAG master oscillator power amplifier with high pulse energy, excellent beam quality, and frequency-stabilized master oscillator as a basis for a next-generation lidar system.

A pulsed, diode-laser-pumped Nd:YAG master oscillator power amplifier (MOPA) in rod geometry, frequency stabilized with a modified Pound-Drever-Hall scheme is presented. The apparatus delivers 33-ns pulses with a maximum pulse energy of 0.5 J at 1064 nm. The system was set up in two different configurations for repetition rates of 100 or 250 Hz. The beam quality was measured to be 1.5 times the diffraction limit at a pulse energy of 405 mJ and a repetition rate of 100 Hz. At 250 Hz with the same pulse energy, the M2 was better than 2.1. The radiation is frequency converted with an efficiency of 50% to 532 nm. This MOPA system will be the pump laser of transmitters for a variety of high-end, scanning lidar systems.

Spatially correlated light emission from a resonant-cavity light-emitting diode.

We present the angular-resolved intensity noise characteristics of a resonant-cavity light-emitting diode under quiet pumping conditions. Measurements by a sensitivity-enhanced lock-in amplifier detection scheme yielded a spatial anticorrelation between the intensity noise of the central and peripheral parts of the emitted far field. Proposals for possible explanations of this anticorrelation from a semiconductor emitter point of view and its consequences for applications in quantum optical imaging are discussed.