Dye Laser Cavity Research Articles

Diode-pumped all-fiber-optic liquid dye laser

We report the experimental results of a fiber-based Fabry–Perot cavity dye laser structure. The structure is transversely pumped by a pulsed blue laser diode through an optical fiber. The active medium used consists of the dye fluorescein sodium dissolved in glycerine. A lasing around 580 nm has been observed when the laser threshold energy of about 46 nJ pulse−1 is reached. The results will contribute to the creation of a fully integrated diode-pumped all-fiber-optic dye laser source.

Stabilization of Transverse Modes for a High Finesse Near-Unstable Cavity

We develop a method to lock a high-finesse near-unstable Fabry–Perot (FP) cavity (F = 7330) to a frequency stable dye laser operating at 605.78 nm using the Pound–Drever–Hall technique. The experimental results show the feasibility of locking this cavity to different transverse modes. This method links the external FP cavity to the dye laser cavity, and a 379 kHz final linewidth of the FP cavity is achieved. Such a near-unstable cavity is potentially useful for cavity-enhanced spontaneous parametric down-conversion to generate narrow-band single photon or photon pairs in different transverse modes.

Study of electronic absorption spectrum of hafnium monobromide molecule in the 550–800 nm region

The electronic absorption spectrum of the HfBr molecule in the 550–800 nm region is studied using the intracavity laser spectroscopy method. The HfBr molecules are produced in plasma formed during a pulse electric discharge in the vapor mixture of hafnium tetrabromide with hydrogen or ammonium. The discharge tube with the mixture is placed in a dye laser cavity. The spectrum recording is conducted with the help of a diffraction spectrograph (resolution power 240000). The high sensitivity of the intracavity method makes it possible to reveal the presence of twenty new bands in the HfBr spectrum with partially resolved rotational structure. By analogy with the HfCl spectrum, the HfBr bands are assigned to the 2Δ3/2–X2Δ3/2 transition. Analysis of the bands is conducted and molecular constants are determined for the ground and excited states:ωe'' = 255.07 cm–1, ωeωe''= 0.86 cm–1, ωe'= 238.31 cm–1, ωeωe'= 1.1 cm–1, B'' = 0.04251 cm–1, B' = 0.04025 cm–1.

A seeded dye laser cavity for intracavity experiments

A seeded dye laser cavity, synchronously pumped by the 2nd harmonic of the Nd:YAG laser has been designed and experimentally tested. The used seed signal was the well defined narrow linewidth output laser signal (▵λ = 0.013 nm) from the excimer-dye laser system. Energy considerations showed that the intracavity laser energy, that can be used for an experimental section inside the cavity, can reach an efficiency of 20% of the pumping energy. The wavelength and linewidth are fully controlled by the wavelength and linewidth of the seeding laser.

Temporal dynamics of high repetition rate pulsed single longitudinal mode dye laser

Theoretical and experimental studies of temporal dynamics of grazing incidence grating (GIG) cavity, single-mode dye laser pumped by high repetition rate copper vapour laser (CVL) are presented. Spectral chirp of the dye laser as they evolve in the cavity due to transient phase dynamics of the amplifier gain medium is studied. Effect of grating efficiency, focal spot size, pump power and other cavity parameters on the temporal behaviour of narrow band dye laser such as build-up time, pulse shape and pulse width is studied using the four level dye laser rate equation and photon evolution equation. These results are compared with experimental observations of GIG single-mode dye laser cavity. The effect of pulse stretching of CVL pump pulse on the temporal dynamics of the dye laser is studied.

A self-quenching picosecond distributed feedback dye laser pumped by a picosecond laser pulse

A tunable single short pulse laser system with a transform–limited bandwidth pumped by a picosecond Nd:YAG laser (ca. 120 ps pulse width) is demonstrated. With this configuration, the relaxation oscillations coming from a distributed feedback dye laser cavity are completely removed. Because the pumping pulsewidth is shorter than the lifetime of dye molecule on the upper laser state, the gain of the laser medium is depleted by the first pulse. The laser wavelength could be precisely tuned with the transform-limited bandwidth (for example, a linewidth of 0.02 nm). After amplification, we obtain a single short laser pulse energy up to 500 μJ at the pulsewidth of 8.2 ps.

Effect of higher protonation on lasing performance of Rhodamine-B in sol–gel glasses

Abstract Three types of Rhodamine-B (Rh-B) impregnated sol–gel samples (mentioned as type-A, type-B, type-C) were prepared. After studying photophysical properties, the dried samples were subjected to laser study under nitrogen laser pumping in a transverse dye laser cavity. Type-B and type-C samples were found to be lasing, while type-A did not show any lasing action. The photostability study of these samples under nitrogen laser pumping showed that Rhodamine-B was more photostable in type-C sol–gel host than in type-B. These results have been explained by taking into account the molecular changes in Rh-B in the sol–gel host matrix.

Correlation between photophysical properties and lasing performances of Rhodamine-19 in three types of sol–gel glass hosts

Rhodamine-19 (Rh-19) incorporated three types of sol–gel samples (mentioned as dope route-I, dope route-II and dip method) were prepared by using two different methods of dye impregnation. The photophysical properties of all the three types of Rh-19 incorporated sol–gel solids were studied by using the UV–Visible absorption and the fluorescence spectroscopy. A single photon counting technique was used to estimate the lifetime of fluorescent species. From the study of fluorescence spectra, the coexistence of dimers (fluorescent and non-fluorescent both) and monomer of Rh-19 was observed. The photophysical properties of Rh-19 were found to be the best in dip sample, medium in dope route-II sample and low in dope route-I sample. After studying photophysical properties, the samples were subjected to laser study under nitrogen laser pumping at 337.1 nm at the rate of 1.5 Hz in transverse dye laser cavity. The highest laser efficiency and photostability of the dye were observed in dip sample, medium in dope route-II sample and small in dope route-I sample. A comparison between photophysical properties and laser performance of these materials showed a very good correlation.

Single mode operation of a narrow bandwidth dye laser using a single prism, grazing incidence grating long cavity

The single mode pulsed dye laser is an attractive tool for many spectroscopic applications. Long cavity tunable dye lasers generally operate in multi-longitudinal modes within the bandwidth of gain profile. Single longitudinal mode oscillation can be obtained by either making the cavity short enough or introducing an additional loss mechanism, in which all modes but one have a gain less than their loss. A new technique to achieve single mode operation in a long cavity dye laser, based on Rhodamine 6G dye in ethanol and ethylene glycol solution, pumped by a high repetition rate copper vapor laser, is reported. This laser, which operates in three modes in grazing incidence grating configuration (cavity length of 16 cm), has been made to lase in single mode by increasing the loss in the resonator through beam walk-off.

On the [formula omitted] state of NaK

The C 1 Σ + state of NaK has been observed up to v ′′=72 in a compilation of measurements from resolved laser induced fluorescence and polarisation labelling spectroscopy experiments. Resolved fluorescence experiments followed single colour optical–optical double resonance (sometimes with the source placed inside a dye laser cavity), or two-colour double resonance using two infrared dye lasers, which excited either the 6 1 Σ + or 3 1 Π electronic states. Fourier transform resolved fluorescence spectra show that low vibrational levels of the 3 1 Π state are efficiently depopulated by collisional electronic energy transfer to nearby vibrational levels of 6 1 Σ + . Equilibrium constants for the C 1 Σ + state of NaK are: T e =17786.75 cm −1 (with respect to the minimum of the electronic ground state), Y 10=69.6123 cm −1, Y 01=0.05919 cm −1.

Continuous pulse duration variation in quenched cavity dye laser

We have suggested a method of generating short pulses with a continuous pulse duration variation from the quenched cavity dye laser (QCDL) system theoretically and experimentally. The XeCL excimer laser pumps a QCDL system to give a continuously varying pulse of duration from 86 to 201 ps as a function of focused pumping thickness in dye cell from 273 to 845 μm. These measurements are in good agreement with the results of numerical analysis. From these results, it is demonstrated that the linear pulse duration variation can be obtained by just changing the focused pumping volume.

Compact 2.5-W 10-kHz Nd:YLF-pumped dye laser.

A 10-kHz pulse repetition frequency dye laser, end pumped by a Nd:YLF laser, is reported. This laser was tunable from 590 to 655 nm, and up to 2.55 W of output power was obtained at the 609-nm peak tuning wavelength. By inserting an etalon into the dye laser cavity and frequency doubling using a beta-barium borate crystal, we obtained up to 125 mW of 308-nm single-etalon-mode output, which shows potential for the performance of airborne measurements of tropospheric hydroxyl radical concentrations.

A comparative study of approaches for spectral control of Ti:sapphire pulsed lasers

The results of a comparative study (theoretical and experimental) of two original approaches for spectral control of two-wavelength pulsed Ti:sapphire (Ti:S) lasers and the most popular conventional methods are presented. Single line operation as a particular case is considered. We compare our own methods: (i) combined dual pulse pumping–passive self-injection locking (DPP–PSIL) and (ii) coupled cavity dye laser injection locking (CCLIL) with the conventional methods: (i) intracavity selection (IS), (ii) PSIL and (iii) traditional injection locking using an external dye laser. The most important criteria—laser efficiency, emission line width, tuning range, spectral purity and buildup time are compared under optimized conditions. The comparison is made using the same pump source with constant output energy in each case. The results serve as a basis for choosing correctly the most suitable spectral control technique for a particular Ti:S laser application. It is shown that the DPP–PSIL method guarantees a remarkable improvement of the Ti:S laser performance (nearly doubling the laser efficiency with the same line width and comparable laser tuning range as IS, combined with a protection of the selectors). The CCLIL approach assures a maximum laser efficiency in narrow line emission in addition to a minimal and reproducible buildup time. The IS method provides a maximal tuning range.

Spontaneous light-polarization symmetry breaking for an anisotropic ring-cavity dye laser

A semiclassical model of a unidirectional anisotropic ring cavity dye laser has been investigated analytically and numerically. In spite of the axial symmetry of the inversion angular distribution and the isotropy of the cavity, polarized initial fluctuations cause spontaneous light-polarization symmetry breaking in the form of alternative circularly polarized waves. Polarization symmetry is restored by increasing the orientational relaxation and pumping rates or the anisotropy of the cavity.

Lasing threshold reduction in grating-tuned cavities

A new geometry for grating-tuned cavities that reduces optical losses from the gratings, lowers the lasing threshold, and enhances the laser output is described and tested. We achieved these enhancements by feeding back into the cavity light that is normally lost through grating reflections. The new geometry is tested on two grazing-incidence dye laser cavities: one that resembles a Littman -Metcalf design and demonstrates the essential principle of the new arrangement, and one that introduces modifications necessary to allow single-longitudinal-mode operation without mode hopping over a tuning range of ~15 cm-1 .

A modular, reconfigurable-cavity, pulsed dye laser for the advanced undergraduate laboratory

The modular pulsed dye laser described is extremely easy to build, is quickly reconfigurable into different laser cavity designs, and is usable for experiments in spectroscopy. The laser can be constructed with readily available optical components and simple hand tools. This laser is designed primarily to illustrate the performance differences of three different dye laser cavity designs: the Littrow grating (Hänsch) cavity, and both the single- and double-grating grazing incidence cavities. In the double-grating configuration, the laser’s linewidth of 0.007 nm is on the order of ten times narrower than many commercially available pulsed dye lasers. Thus the laser also has excellent performance as a spectroscopic tool. Construction, typical performance, and application details are described.

Orientational-relaxation dependent bichromatic operations of a ring cavity dye laser with polarized pumping

Based on semiclassical equations, a set of multi-frequency solutions for the ring cavity dye laser with polarized pumping has been derived. As an example, it has been shown that frequency splitting for the bichromatic operation depends on pumping anisotropy and the rate of Brownian rotation of dye molecules and excitation energy migration.

Simple source of subnanosecond dye laser pulses

A very simple dye laser cavity generates stable single pulses of less than 300-ps duration and several microjoules of energy when pumped by about 50 µJ of an 8-ns pulse from a low-pressure nitrogen laser. The pulses are produced by a mechanism similar to the "quenched" resonator setup. A theoretical description is given, showing good agreement with the observed results. Achievable improvements are described, which would reach the tens of picosecond range.

Photoacoustic analysis of stimulated emission in pulsed dye lasers

Stimulated emission in pulsed dye lasers was characterized in several experimental conditions by analyzing the changes in the acoustic signals generated in a dye solution, with the dye laser cavity either active or inhibited (i.e., by blocking the optical path or misaligning of the optical components). Pump energy threshold, optimum dye concentration, tuning range and maximum-emission wavelength of a rhodamine 6G dye laser were measured by this method. An approximate model for the photoacoustic signal generation consistent with the experiments is presented.

Fixed-wavelength operation of a copper-laser-pumped dye laser injection seeded by low-power He–Ne lasers

The design and operating characteristics of a dye laser pumped by a 3-W copper-vapor laser (CVL) and injection seeded by low-power (1-5 mW) He-Ne lasers at 633 nm are reported. An extremely simple optical arrangement is used wherein the output mirror of the He-Ne laser and a third mirror form the dye laser cavity. Laser efficiency in fixed-wavelength operation has been investigated for variable CVL pump power, He-Ne injection power and polarization, and cavity output coupling for a standard Rhodamine 590/Rhodamine 640 dye solution. Over 90% of free-running (unseeded) laser power is obtained in fixed-wavelength (seeded) operation at low CVL pump powers (≤1 W), dropping to approximately 60% at 3-W pump power. Maximum CVL pump to dye laser optical conversion efficiency in narrow-band, fixed-wavelength operation at 633 nm was 12%.