Single-mode dye laser

SINGLE MODE DYE LASER BEAM Figure 9. Schematic of energy-transfer experiment. 

The simplest method to obtain high-resolution spectra is to replace the pulsed dye laser with a CW single-mode dye laser. As Steimle and co-workers have demonstrated in a series of beautiful experiments, this... 

Electric field spectroscopy with a tunable laser uses the Stark effect to provide selective modulation of specific branches, but does not permit the direct measurement of dipole moments. There are a number of molecules in which a tunable laser has been used to scan Stark-split line profiles of lines of known assignment. One such example is illustrated in figure 7 this shows the five M components of the P3 (3) line in the electronic 0-0 band of the HCF radical near 17238.4 cm , recorded using a single-mode dye laser and an electric field of 19.25 kV cm in parallel polarisation. The analysis of many Stark-split spectra using eqns 2-4 leads to the following values for the a-axis component of the dipole moment in the two states ... 

Estimate the fluorescence detection rate (number of detected fluorescence photons/s) on the Na transition 5s -> 3p, obtained in the Doppler-free free-photon experiment of Fig. 2.32, when a single-mode dye laser is tuned to v/2 of the transi-... 

The reduction of the velocity distributions n(Vx) and n(Vz) can be measured with different spectroscopic techniques. The first method is based on measurements of the Doppler profiles of absorption lines (Fig. 4.11). The beam of a single-mode dye laser is split into one beam that crosses the molecular beam perpendicularly, and another that is directed anticollinearly to the molecular beam. The maximum com of the Doppler-shifted absorption profile yields the most probable velocity i p = (o>o — com)/k, while the absorption profiles of the two arrangements give the distribution n(v ) andn(u L) [408, 409]. 

Fig. 4.16 Section of the excitation spectrum of NO2 obtained under different experimental conditions (a) in a vapor cell at T = 300 K, p(N02) = 0.05 mbar (b) in a pure NO2 beam at rot = 30 K (c) in a supersonic argon beam seeded with 5 % NO2 at rot — 3 K, where (a-c) were excited with a dye laser with 0.05 nm bandwidth [413] (d) 0.01 nm section of (b) recorded with a single-mode dye laser (1 MHz bandwidth) [414]...

The Doppler-broadened baekground with the residual Doppler width from the divergence of the molecular beam ean completely be eliminated by chopping the two laser beams at two different frequeneies fi, fi, and monitoring the signal at the sum frequency /i -I- /2 (intermodulated fluorescence. Sect. 2.3.1). This is demonstrated by the insert in Fig. 4.25. The linewidth of the Lamb dips in Fig. 4.25 is below 1 MHz and is mainly limited by frequeney fluctuations of the cw single-mode dye laser [453],... 

Fig. 10.4 Selective excitation of a wanted isotope by a pulsed, amplified single-mode dye laser with subsequent ionization by an excimer laser and mass-selective detection behind a time-of-flight spectrometer...

Transform limited pulses of a duration of 9 ns with a very stable center frequency were generated as follows A tunable single mode dye laser with a bandwidth of 2 MHz was pulsed with the help of an acousto-optical modulator. For the fluorescence lifetime experiments pulses of 9 ns FWHM and a separation of 1 ps were used. The laser pulses were focused onto a pinhole with a diameter of 5 pm and illuminated about 100 pm of the sample crystal. A set of lenses imaged the emerging fluorescence onto a fast photomultiplier. Optical cutoff filters removed scattered laser light from fluorescence. Recording times up to 1200 s were necessary to obtain reliable statistics for the fluorescence decay curves. The laser had to be stabilized onto a fixed frequency during the full measurement time. 

Fig.4.69a-e. Output signals at the poly-chromator and the three diode arrays of the FPI wavemeter, which had been illuminated by a cw HeNe laser oscillating on two axial modes (a-d). The lowest figure shows the ring intensity pattern of an excimer-pumped single-mode dye laser measured behind a FPI with 3.3 GHz free spectral range [4.70]... 

Fig. 5.56a,b. Discontinuous tuning of lasers (a) part of the neon spectrum excited by a single-mode dye laser in a gas discharge with Doppler-limited resolution, which conceals the cavity mode hops of the laser (b) excitation of Na2 lines in a weakly collimated beam by a single-mode argon laser. In both cases the intracavity etalon was continuously tilted but the cavity length was kept constant... 

Two collinear cw beams from a stable single-mode argon laser and a tunable single-mode dye laser are mixed in a LiNb03 crystal (Fig. 5.116). For 90° phase matching of collinear beams, the phase-matching condition... 

Estimate the fluorescence rate (number of fluorescence photons/s) on the Na transition 5s -> 3p, obtained in the Doppler-free free-photon experiment of Fig. 7.28, when a single-mode dye laser is timed to v/2 of the transition 3s 5s in a cell with a Na density of n = 10 cm. The laser power is P = 100 mW, the beam is focused to the beam waist wo = 10 cm and a length L = 1 cm around the focus is imaged with a collection efficiency of 5% onto the fluorescence detector. 

S. Saikan Nitrogen-laser-pumped single-mode dye laser. Appl. Phys. 17, 41 (1978)... 

N. Wang, V. Gaubatz Optical frequency doubling of a single-mode dye laser in an external resonator. Appl. Phys. B 40, 43 (1986)... 

---