JPH0433388A - Vertical excitation wavelength variable dye laser oscillator - Google Patents

Abstract

PURPOSE:To drive by a pump laser having a high oscillation repetition frequency by employing a nozzle capable of forming a dye jet to be injected to a dye circulator at a high speed. CONSTITUTION:In order to perform a stable single vertical mode oscillation, a nozzle 1 for forming a dye jet 2 has a shape of uniform thickness of dye solution in a pump laser light emitting unit and scarcely generating a disorder on the surface. In order to perform a single vertical mode oscillation, the structure of a laser oscillator is formed in a Littmann type grading incidence structure, and the length of the resonator is shortened. One vertical mode and wavelength are selected by an oblique incident grating 4 and a totally reflecting mirror 5.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a longitudinally pumped wavelength tunable dye laser oscillator.

Specifically, the present invention relates to a single longitudinal mode oscillation wavelength tunable laser oscillator with longitudinal excitation using a dye jet and having a Littmann-type grazing incidence structure driven by a high repetition rate pump laser.

(Prior Art) A laser oscillator with a Littmann-type grazing incidence structure is composed of an oblique incidence grating, a tuning mirror for wavelength selection, a laser medium, and a total reflection mirror forming a resonator. The tuning mirror of this resonator is then rotated around a special pivot point. Therefore, the cavity length changes as the wavelength is swept,
Even when sweeping wavelengths over a wide range, the same longitudinal mode can be maintained without mode hopping.

In order to achieve single longitudinal mode oscillation with a laser having such a structure, it is necessary that the laser medium (dye solution) be uniform and undisturbed, that the resonator length be short, and that the longitudinal heptad spacing be wide. Therefore, in order to satisfy these two conditions,
The laser medium is flowed through a thin glass dye cell at a speed that does not cause turbulence, and is pumped by a pump laser to achieve single longitudinal mode oscillation.

Due to this structure of the dye circulation part, the dye solution cannot be circulated at high speed, and there is a large restriction on the number of oscillation repetitions of the pump laser, and the field of application is limited to some areas such as spectroscopy.

(Problem B to be Solved by the Invention) An object of the present invention is to provide a longitudinally pumped wavelength tunable dye laser oscillator that solves the above-mentioned problems.

(Means for Solving the Problem) As a result of intensive research to achieve this objective, the inventor of the present application has solved this problem by adopting a nozzle that can create a dye jet that is ejected at high speed into the dye circulation section. We came up with the idea that this is possible, and came to invent the longitudinally pumped wavelength tunable dye laser oscillator of the present invention.

In order to achieve stable single longitudinal mode oscillation, the nozzle for creating the dye jet has a shape in which the thickness of the dye solution is uniform at the pump laser beam irradiation part and the surface is not disturbed.

The structure of the laser resonator is a Liftman type grazing incidence structure to achieve single longitudinal mode oscillation, and the length of the laser resonator is shortened. One longitudinal mode and wavelength selection is performed using an oblique incidence grating and a total reflection mirror.

In the present invention, the dye can be ejected at high speed by using a jet jet that is ejected at high pressure into the dye circulation section, so it can be driven by a pump laser with a high oscillation repetition rate.Furthermore, the geometric Since a thin dye jet is used, the resonator length can be shortened, which widens the longitudinal mode spacing compared to previous models, making it possible to provide a wavelength tunable laser oscillator that oscillates in a more stable single longitudinal mode.

As a result, the longitudinally excited wavelength-tunable dye laser oscillator of the present invention can be used in many fields such as isotope separation laser oscillators that require a high oscillation repetition rate.

(Example) Next, the present invention will be described in more detail with reference to Examples.

We prototyped a wavelength tunable dye laser resonator as shown below.

The laser cavity length is 54 mm, and the dye jet thickness is 0. l nv+, and the pump discharge pressure was set to 80 psi, which resulted in the most stable longitudinal mode.

A silver vapor laser with an oscillation repetition rate of 6°5 KHz and an output power of 5 was used as the pump laser. 5 of the two wavelengths of 510 nm and 578 nm generated by the pump laser
10 nm light was selected by a dichroic mirror and focused onto the dye jet by a lens with a focal length of 1.2 m. The longitudinal mode structure of the output light of the wavelength tunable dye laser was measured using a Fapley Bellow etalon interferometer.

Experiments confirmed that the prototype wavelength-tunable dye laser oscillator oscillated in a single longitudinal mode.

In wavelength tunable dye laser oscillators without a control mechanism to maintain a constant cavity length, the length of the cavity changes slightly due to environmental temperature changes, vibrations, etc., and as a result, the oscillation frequency changes. During this change, two longitudinal modes may occur simultaneously. At this time, the interval between the two longitudinal moats is always a frequency interval determined by the length of the resonator. As a result of the measurement, it was confirmed that the spacing between the two modes was in good agreement with the value determined from the resonator length.

The longitudinally pumped wavelength tunable dye laser oscillator of the present invention includes (oscillator for a wavelength tunable laser system for separation and recovery of 11-shell isotopes, (2) oscillator for a wavelength tunable laser system for uranium enrichment, (3) nuclear fuel reprocessing disposal) It can be applied to an oscillator for a wavelength tunable laser system for separating and recovering long half-life nuclides or useful fission products from objects, and (4) a light source for precision spectroscopy.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a longitudinally pumped wavelength tunable dye laser oscillator of the present invention. In the figure, 1 is a nozzle for ejecting the laser medium, 2 is a dye jet, 3 is a pump for dye circulation, 4 is an oblique incidence grating for selecting a single longitudinal mode, and 5 is for selecting a wavelength. The total reflection mirror 6 forms a laser resonator. The total reflection mirror 7 excites the dye. The pump laser beam 8 is a wavelength variable laser beam.

Claims (4)

[Claims] (1) A longitudinally pumped wavelength-tunable dye laser oscillator that oscillates in a single longitudinal mode using a dye jet. (2) The longitudinally excited wavelength-tunable dye laser oscillator according to claim 1, wherein the laser catalyst (dye solution) is ejected from a nozzle at high speed. (3) The longitudinally pumped wavelength tunable dye laser oscillator according to claim 1 or 2, wherein the structure of the resonator is a Littmann-type grazing incidence structure. (4) The longitudinally pumped wavelength tunable dye laser oscillator according to any one of claims 1 to 4, which is pumped with a pulsed laser having a high oscillation repetition rate.