ABSTRACT
Laser cleaning provides art and heritage conservators with an alternative means to restore objects when traditional chemical and mechanical methods are not viable. However, long (>nanosecond) laser pulses can cause unwanted damage from photothermal processes and provide limited control over ablation depth. Ultrashort (
ABSTRACT
Narrowband pulsed 822 nm signal radiation from an injection-seeded optical parametric oscillator (OPO) system is used to record fluorescence-detected sub-Doppler two-photon excitation (TPE) spectra of atomic cesium. An optical-heterodyne technique is used to monitor the frequency chirp as well as the fluctuating central frequency of successive OPO output pulses, thereby providing a novel way to record sub-Doppler TPE spectra. The measured TPE linewidth approaches the ultimate limit imposed by the Fourier transform of the pulse's temporal profile, demonstrating the utility of this system for pulsed laser spectroscopy applications that require the highest possible resolution.
ABSTRACT
Optical-heterodyne measurements are made on ~842-nm signal output of an injection-seeded optical parametric oscillator (OPO) based on periodically poled KTiOPO4 pumped at 532 nm by long (~27-ns) pulses from a Nd:YAG laser. At low pump energies (
ABSTRACT
An injection-seeded optical parametric oscillator (OPO), based on periodically poled KTiOPO4 and pumped by a frequency-doubled, nanosecond-pulsed Nd:YAG laser, generates continuously tunable, single-longitudinal-mode, pulsed output at approximately 842 nm for high-resolution spectroscopy. Optical-heterodyne measurements show that the OPO frequency chirp increases linearly with detuning from the free-running (unseeded) OPO frequency and can be maintained as low as 10 MHz. Other factors affecting chirp are identified.
