A narrow-band injection-seeded pulsed titanium:sapphire oscillator-amplifier system with on-line chirp analysis for high-resolution spectroscopy

Abstract

A narrow-band tunable injection-seeded pulsed titanium:sapphire laser system has been developed for application in high-resolution spectroscopic studies at the fundamental wavelengths in the near infrared as well as in the ultraviolet, deep ultraviolet, and extreme ultraviolet after upconversion. Special focus is on the quantitative assessment of the frequency characteristics of the oscillator-amplifier system on a pulse-to-pulse basis. Frequency offsets between continuous-wave seed light and the pulsed output are measured as well as linear chirps attributed mainly to mode pulling effects in the oscillator cavity. Operational conditions of the laser are found in which these offset and chirp effects are minimal. Absolute frequency calibration at the megahertz level of accuracy is demonstrated on various atomic and molecular resonance lines.

High-resolution laser spectroscopy of long-lived plutonium isotopes

“…In principle, the injection-locked laser should be lasing at a frequency very close to that; however, effects such as a nonoptimal lock, cavity mode pulling, and frequency chirps caused by the pump laser pulse may introduce inaccuracies [45,46]. The chirp effect, however, is a constant offset on the frequency axis and therefore valid for all isotopes.…”

Highly scannable injection seeded nanosecond Ti:sapphire ring laser

“…8). This kind of frequency shift was analysed in dye amplifiers [17], in OPOs [9] and Ti:Sa [6,11]. While in a non-linear medium the shift is primarily due to the phase mismatch between the interacting waves, in fluorescent media it is the gain dependence of the refractive index, because of the varying population inversion density that is responsible for the frequency distorsions.…”

VUV-synchrotron absorption studies of N2 and CO at 900K

“…The actual cavity resonance in the presence of the pump pulse is then frequency-shifted with respect to the locking point of the unpumped cavity. The frequency shift can be separated into contributions from a thermal change of the refractive index ∆n th and an effect from the population inversion ∆n inv in the Ti:Sa crystal [64]. The total effective frequency offset, typically tens of MHz in the fundamental f IR , can be compensated by controlling the lock setpoint of the Ti:Sa oscillator, e.g.…”

“…An extensive description of the laser system and its operation can be found in Ref. [64], while its performance in the measurements on the…”