Rhodamine 6G Dye Laser Research Articles

Spectral narrowing of a dye laser oscillation using an intracavity vapor prism

A new method for narrowing the oscillation spectrum of a broad-band dye laser is reported in this paper. The narrowing is achieved by a vapor prism placed inside the laser cavity, which is based on an anomalous dispersion of the atomic vapor so that the narrowing effect occurs only in the vicinity of the absorption line. Using a sodium vapor prism inside a Rhodamine 6G dye laser cavity, an oscillation linewidth less than 0.01 nm was attained at a sodium temperature of 320°C.

Resonance Raman spectra of Cu‐porphin‐d4(meso) and Ni‐porphin, and the infrared spectrum of Cu‐porphin‐d4

AbstractThe resonance Raman spectra are presented for Ni‐porphin and Cu‐porphin‐d4(meso) as dilute solutions in CS2 and C2Cl4 using an Ar+ laser and a tunable Rhodamine 6G dye laser. The Raman features are assigned to the different vibrational species on the basis of their depolarization data. The assignment of 14 features in the spectrum of Cu‐porphin‐d4 and 13 features in the spectrum of Cu‐porphin and Ni‐porphin is discussed by comparing the spectra of the three molecules. Also the infrared spectrum of Cu‐porphin‐d4 as a solid dispersed in CsI matrix is reported for the 200–2000 cm−1 region.

A high-power pulsed xenon ion laser as a pump source for a tunable dye laser

An inexpensive pulsed xenon ion laser with peak power outputs up to 4 kW has been constructed and used as a pump source for a tunable rhodamine 6G dye laser with a 0.25-Å bandpass in the yellow-red range of the spectrum. The dye laser is tunable from 5465 to 6300 Å. Over 50 W are obtained at the peak of the tuning range.

Optical–optical double resonance laser spectroscopy of BaO

BaO molecules were sequentially excited by collinearly propagating radiation from two cw lasers, an argon ion laser (488.0 and 496.5-nm lines) and a tunable (560–630 nm) rhodamine 6G dye laser. This sequential excitation technique, called optical–optical double resonance (OODR), is a special case of two-photon spectroscopy in which two visible or uv wavelength photons of different frequencies resonantly excite a molecule from an initial level (v″,J″) to a final level (v*,J*) by way of a real intermediate level (v′,J′). Two types of optical double resonance experiments were performed on BaO. The first, excitation spectroscopy, revealed 19 vibronic levels of 1Σ+ electronic symmetry between 36 490 and 38 620 cm−1 above E (X 1Σ,re). These 19 1Σ+ levels belong to two or more perturbed electronic states. No 1Π levels were found, although levels belonging to the upper state of the BaO B (1Π) –X 1Σ Parkinson bands occur in this energy region. The second type of experiment, photoluminescence spectroscopy, enabled observation of extended rotationally resolved photoluminescence progressions out of various two-photon-excited levels (v*,J*) into BaO X 1Σ (v″=0–34). Vibrational energies and rotational constants obtained from these photoluminescence progressions were used to construct an RKR potential energy curve for BaO X 1Σ+ through v″=40, from which it was shown that the X 1Σ+ and a 3Π curves cross at r=0.276 nm and E=22 750 cm−1 [above E (X 1Σ,re)]. Laser frequency jitter of less than 10−3 cm−1 resulted in large intensity fluctuations of the OODR signal, implying that the double resonance linewidth was narrower than the Doppler width of the (v′,J′) → (v*,J*) transition. This sub-Doppler width effect resulted from excitation of (v′,J′) molecules that were velocity selected relative to the laser propagation direction.

Tunable picosecond transient stimulated Raman scattering in ethanol

Transient stimulated Raman scattering (TSRS) of picosecond dye laser pulses in ethanol has been investigated experimentally. In particular some temporal features of TSRS from the C-H stretching mode (2928 cm -1) in ethanol have been studied with a Photochron II streak camera with subpicosecond time resolution. It is shown that the use of TSRS provides a simple method for producing picosecond pulses tunable over the spectral region ≈492–532 nm and 691–772 nm by tuning a passively mode-locked Rhodamine 6G dye laser from 575–630 nm.

Resonance Raman spectra of Cu-1:3:5:7-tetramethyl porphin and Cu-1:2:3:4:5:6:7:8-octamethyl porphin

Resonance Raman spectra of Cu-1:3:5:7-tetramethyl porphin and Cu-1:2:3:4:5:6:7:8-octamethyl porphin have been obtained both in dilute CS2 solution and as solids dispersed in KBr matrices using the Ar+ and tunable Rhodamine 6G dye lasers. The solution data for Cu-octamethyl porphin show that its rigorous molecular symmetry in solution is D4h, while the spectral data for Cu-tetramethyl porphin are consistent with C4h molecular symmetry. Assignments for some of the stronger bands are discussed by comparing the spectra of these two molecules with other planar metalloporphins and porphyrins.

Amplification and laser action in a laser dye pumped by a copper-vapor laser

The 5106-Å output of a 250-mW copper-vapor laser has been used to obtain laser action in a Rhodamine 6G dye laser. The high gain of such a copper-vapor laser pumped dye solution has been demonstrated by amplifying the 5782-Å output of the same copper-vapor laser.

Stimulated emission of cresyl violet pumped by N2 laser or rhodamine 6G dye laser

Cresyl violet solutions have been shown to lase when pumped with a N2 laser or a rhodamine 6G dye laser. In the latter case the efficiency is much higher, and for appropriate solution concentrations the dye lases at the wavelength peak of its spontaneous emission. Under these conditions, the gain is so high that superradiance is obtained using only a 10−kW exciting pulse with 10% lasing efficiency.

Resonance Raman spectra of Cu-etioporphyrins I, I-m e s o-d4, and IV

Resonance Raman spectra obtained using the Ar+ and tunable Rhodamine 6G dye lasers are presented for the position isomers Cu−etioporphyrin I and IV in dilute (10−4 M) solution. The spectra show significant differences in several vibrations enabling the molecules to be distinguished. Several anomalously polarized (ρl ≳ 3/4) vibrations are observed which show dispersion of the depolarization ratios. The dispersion of ρl is interpreted as arising from reduction of chromophore symmetry from its idealized D4h. The solution data for Cu−etioporphyrin I and Cu−etioporphyrin IV are consistent with C4h symmetry and C2v symmetry, respectively, thereby demonstrating the sensitivity of resonant Raman scattering to slight perturbations of the chromophore due to peripheral substituents. Resonance Raman data are also presented for the deuterated analog Cu−etioporphyrin I (meso−d4). Several shifts in the vibrational modes are observed and possible vibrational assignments are discussed.

Resonance Raman spectra of copper-porphin

Resonance Raman spectra of copper-porphin in solution have been obtained using the tunable rhodamine 6G dye, Ar+, and HeCd lasers for excitation. Several bands show variation of intensity with excitation wavelength and many combination and overtone bands have been observed with 5145 Å excitation. Depolarization ratios for the two anomalously polarized bands [ρl > (3/4)] at 1322 and 1587 cm−1 remain constant (∼45) with all the exciting wavelengths in the α and β absorption regions while some polarized bands show variation of their ρl values. It is shown that the rigorous molecular symmetry of Cu-porphin in solution is D4h. Symmetry species of the vibrational modes have been assigned.

An unstable-resonator flashlamp-pumped dye laser

A negative-branch confocal unstable resonator has been found to significantly improve the beam quality of a coaxial flashlamp-pumped rhodamine 6G dye laser. In a performance comparison with a conventional parallel-plane mirror resonator, over an order-of-magnitude increase in laser beam radiance has been measured. The negative-branch unstable resonator demonstrated relatively uncritical alignment sensitivity.

Dependence of the spectrum of 100 J rhodamine 6G dye laser on the spectral composition of the pumping light for various dye concentrations

Dependence of the spectrum of 100 J rhodamine 6G dye laser on the spectral composition of the pumping light for various dye concentrations

Nd-glass laser with three-dimensional optical waveguide

Room-temperature laser operation in a three-dimensional Nd-glass waveguide is reported. The waveguide was fabricated by a double-diffusion process with ion migration. A Nd-glass laser, 4 mm in length, was end-pumped at 590-nm wavelength with a pulsed Rhodamine 6G dye laser. The threshold power for the Nd-glass waveguide laser was about 18 μJ, which was nearly one-half of that for a conventional Nd-glass laser without guiding structure. The measured value of the threshold for a waveguide laser agrees with the theoretical calculation.

Pulse evolution in mode-locked quasi-continuous lasers

Various models of a passively mode-locked quasi-continuous laser are discussed and the evolution of pulses in various cavity configurations is traced. In certain circumstances, the combined action of amplifier and absorber saturation is shown to lead to rapid pulse compression even when the pulse duration is far shorter than the relaxation time of either nonlinear component. The results are in good agreement with recent streak- camera measurements involving the pulsed Rhodamine 6G dye laser and satisfactorily explain the efficient generation of picosecond pulses in CW dye-laser systems. The same pulse-compression mechanism can probably be used to generate ultrashort pulses in other quasi-continuous lasers.

New Saturable Absorbers for Rhodamine 6G Dye Laser and the Generation of Picosecond Pulses

New Saturable Absorbers for Rhodamine 6G Dye Laser and the Generation of Picosecond Pulses

Vortex Stabilized Flashlamps for Dye Laser Pumping

A unique vortex gas flow stabilized flashlamp has been developed for dye laser pumping. With a 2-musec current pulse the flashlamp can be operated at up to 250 J/pulse and can be run at a pulse repetition rate of up to 20 pulses/sec. At 200 J/pulse the useful lamp lifetime is several hundred thousand shots. Used for pumping the rhodamine 6G dye laser, the lamp has produced a 10-W average dye laser output.

NdLa pentaphosphate laser performance

Laser operation is reported in a new crystalline material with high Nd content (2 × 1021 cm−3) whose concentration quenching is smaller than in other hosts. This material, NdLa pentaphosphate (Nd0.5La0.5P5O14) in the form of a 35-μm-thick crystal platelet was pumped with a pulsed Rhodamine 6G dye laser. The oscillation threshold with feedback from the uncoated surfaces was [inverted lazy s] 20 μJ of absorbed pump light. This indicates an optical gain coefficient of [inverted lazy s] 800 cm−1 corresponding to an excitation of more than half of the Nd ions in the material. This high gain resulted in a compression of the cavity mode spacing by a factor of 14. Using external mirrors, cw oscillation with a threshold of 25 mW absorbed power of an argon laser was achieved with a 1.4-mm-thick crystal. Measured parameters of the lasers are in good agreement with theory.

Optimizing the emission characteristics of a rhodamine 6G dye laser: Limits of the applications of the coaxial flashlamp as pump source for organic dye lasers

The efficiency of the Rhodamine 6G dye laser is theoretically investigated in the special case of intense flashlamp excitation. A serious limitation of the energy and of the pulse repetition rate of coaxial-flashlamp excited dye lasers is given by the ultrasonic wave initiated by the electrical discharge and which propagates through the dyecell during the laser emission.

Buildup of picosecond pulse generation in passively mode-locked rhodamine dye lasers

The buildup of picosecond pulses in a passively mode-locked rhodamine 6G dye laser has been directly studied with a picosecond streak camera. It is shown how a single isolated picosecond pulse evolves from the initial intensity fluctuations.

Picosecond pulses from a passively mode-locked cw dye laser

Stable passive mode-locking of a cw rhodamine 6G dye laser has been achieved using a simple, end-pumped, internal lens cavity. Direct measurements using an ultra-fast image converter streak camera, with picosecond time resolution, show that the laser output consists of isolated picosecond pulses separated by the 8 nsec round-trip time of the cavity. Pulse durations as short as 4.3 psec have been observed.