Widely tunable single-longitudinal-mode pulsed dye laser

A Hybrid Self-Seeded Ti:sapphire Laser with a Pumping Scheme Based on Spectral Beam Combination of Continuous Wave Diode and Pulsed DPSS Lasers

A wide variety of applications require high peak laser intensity in conjunction with a narrow spectral linewidth. Typically, injection-locked amplifiers have been employed for this purpose, where a continuous wave oscillator is amplified in a secondary external resonant amplifier cavity using a pulsed pump laser. In contrast, here we demonstrate a setup that combines a CW Ti:sapphire oscillator and pulsed amplifier in a single optical cavity, resulting in a compact system. Dichroic beam combination of blue wavelength semiconductor diodes and the green wavelength of a Nd:YAG laser allowed the simultaneous excitation of the Ti:sapphire crystal by both continuous wave and pulsed pump sources. A linewidth of <2MHz is achieved in continuous wave operation, while the linewidth increases to about 10MHz in the combined CW + pulsed mode with a pulse duration of 73ns. A peak pulse intensity of 0.2kW is achieved, which should enable efficient single-pass second harmonic generation in a nonlinear crystal.

Note: Pulsed single longitudinal mode optical parametric oscillator for sub-Doppler spectroscopy of jet cooled transient species

We present a pulsed single longitudinal mode optical parametric oscillator that was recently constructed for sub-Doppler spectroscopic studies of transient species in a supersonic slit jet expansion environment. The system consists of a Littman-type grazing-incidence-grating resonator and a KTP crystal and is pumped at 532 nm. By spatially filtering the pump laser beam and employing an active cavity-length-stabilization scheme, a frequency down-conversion efficiency up to 18% and generation of Fourier-transform limited pulses with a typical pulse duration of ∼5.5 ns and a bandwidth less than 120 MHz have been achieved. In combination with a slit jet expansion, a sub-Doppler spectrum of SiC₂ has been recorded at ∼498 nm, showing a spectral resolution of Δν/ν ≈ 6.2 × 10^-7.

Self-seeding of a pulsed double-grating Ti:sapphire laser oscillator

A self-seeded pulsed double-grating Ti:sapphire laser oscillator consisting of a grazing incidence cavity geometry with a pair of gratings and a standing-wave cavity pumped by a frequency-doubled Nd:YAG laser was developed and characterized. With self-seeding, narrow-linewidth single-longitudinal-mode (SLM) operation and SLM scanning were possible with a reduced lasing threshold, which was desirable for the intended applications.

Single-mode near-infrared optical parametric oscillator amplifier based on periodically poled KTiOPO4

A singly resonant, single-axial-mode, optical parametric oscillator (OPO) based on periodically poled KTiOPO4 (PPKTP) is reported. Signal (1.68 micron) and idler (2.90 micron) optical bandwidths have been narrowed to <400 MHz by use of a diffraction grating at grazing incidence. The OPO generates 370 microJ of signal radiation when pumped by 3.1 mJ of 1.064-micron radiation. We implemented a single-pass PPKTP amplifier to yield 2.15-mJ signal and 1.17-mJ idler radiation without broadening the spectral bandwidths.

Frequency locking of a pulsed single-longitudinal-mode laser in a coupled-cavity resonator

The performance of a novel resonator that couples a grazing-incidence and a linear cavity is reported. The coupling secures single-longitudinal mode, TEM(00), higher-efficiency and lower-threshold operation. By use of Ti:sapphire as the gain medium, a slope efficiency of 23% and a 100-nm tuning range are reported. A model is explained that fully predicts the mode behavior of the resonator and that can be used to optimize the cavity for single-mode operation. We have developed computer control of the cavity, which is simple in design and is used to lock the <200-MHz bandwidth mode to +/-40 MHz. A 4.8-GHz scan has also been demonstrated.

Precisely tunable, narrow-band pulsed dye laser

Anarrow-band, precisely tunable dye laser pumped by an injection-seeded YAG laser is described. The laser achieves an output of 100 mJ/pulse and 40% efficiency when one uses Rhodamine 6G dyes. The output pulse is Gaussian both in time and spatial profile. The laser oscillator employs an intracavity étalon that is repetitively pressure scanned over one free spectral range while the grating successively steps to consecutive étalon modes. We pressure scanned the étalon under computer control using a bellows. Methods are described for calibrating the tuning elements for absolute precision. We demonstrated that the laser has an absolute precision of ±0.4 pm over a 1.0-nm scan. This accuracy is achievable over the wavelength range of a dye.

Self-seeding in a dual-cavity-type pulsed Ti:sapphire laser oscillator

We have constructed a self-seeded Ti:sapphire laser oscillator by using a dual-cavity configuration that consists of a Littman configuration cavity and a partially reflecting feedback mirror. This configuration can be decomposed with two kinds of cavity, a grazing-incidence cavity and a standing-wave cavity. The former behaves as an injection seeder and the latter as a slave oscillator. This Ti:sapphire laser system is capable of delivering a continuously tunable laser pulse with a narrow linewidth. Injection at the laser emission region of the free-running Ti:sapphire laser resulted in essentially complete energy extraction.

Two-step selective photoionization of rubidium by using a Ti:sapphire laser

A pulsed Ti:sapphire laser (TSL) is applied for what is, to our knowledge, the first time to laser isotope separation. A collimated beam of a rubidium atom with a natural isotope composition ((85)Rb, 72%; (87)Rb, 28%) is excited selectively from the ground state to the 5(2)P(3/2) state by irradiation of the single-longitudinalmode TSL, and is photoionized by successive UV radiation. Ion spectra of each isotope indicate that each isotope is selectively photoionized.