KR20020054505A - A transfer for Raman laser apparatus - Google Patents

Abstract

PURPOSE: A raman type laser apparatus is provided to prevent lenses from being damaged by means of light reflected in an apparatus for converting a wavelength of laser and to minimize a demolition of methane gas in the apparatus for converting the wavelength of laser. CONSTITUTION: A raman type laser apparatus comprises a resonator for generating a pulse typed laser and an apparatus(200) for converting a laser having a short wavelength into a laser having a long wavelength. The apparatus(200) for converting the wavelength of the laser includes a chamber(210) in which methane gas is filled up under an atmospheric pressure of about 80 in order to confuse and convert a laser light having a short wavelength of 1.064um into a laser light having a long wavelength of 1.54um, a light collecting lens(140) which is disposed at an end of the chamber(210) to collect incident lights, and a lens(150) which is disposed at the other end of the chamber(210) to convert the collected lights into a parallel lights.

Description

A transfer for Raman laser apparatus

The present invention relates to a laser device, and more particularly, to a Raman laser device in which a lens of a converter for converting a short wavelength laser light into a long wavelength Raman laser is improved.

In general, the Raman laser device of the laser device converts a short wavelength of 1.064㎛ amplified and oscillated from the pump resonator by the Raman induced Brillouin scattering in methane gas to a long wavelength of 1.54㎛ harmless to the human eye Equipped.

As shown in FIG. 1, the converter 10 of the conventional Raman laser apparatus includes a cell chamber 20 having a cylindrical shape, and converges and collimates light provided from a pump resonator at both ends of the chamber 20. The converging lens 40 and the collimating lens 30 are installed, and high-pressure methane gas is filled in the chamber 20 to induce Raman-induced scattering of short wavelength light emitted into the chamber 20. .

In the Raman laser device, the laser beam emitted from the pump resonator emits a strong focused beam inside the converter 10 filled with high-pressure methane gas for Raman induced scattering and Brillouin scattering.

Here, since the focusing lens 30 and the collimating lens 40 installed in the conventional Raman laser device are of the biconvex type, the laser beam returned after the induced Raman Brillouin scattering action is particularly focused inside the converter 10. There is a problem that damages the inner coating portion of the focusing lens 30 by reflecting back to the inner surface side.

In addition, in the conventional biconvex type biconvex type lens 30 and 40, as shown in FIG. 2, the incident rays of the biconvex type are first refracted axially from the outer surface of the lens 30 and 40. After the second refraction in the same direction on the inner surface of the lens 30, 40 is again.

That is, since the angle of incidence θ ₁ into the converter 10 is large, the area of the image diameter I ₁ of the laser beam inside the converter 10 is reduced, resulting in a relatively large energy density. .

Focus density at this time {Power density: P = [(E / T) / A], E: output energy (mJ), T: time (sec), A: cross-sectional area (cm 3)} is about 10 GW / cm ² In general, when the concentration density is about 10 GW / cm ² or more, the methane gas inside the converter 10 starts to be destroyed by the focused beam at this time, and the destroyed methane gas has a large amount inside the converter 10. Carbon is generated.

In addition, the carbon proceeds toward the focusing lens 30 and the collimating lens 40, and sticks to the inner surfaces of the lenses 30 and 40, thereby lowering the operating efficiency and lifespan of the laser device.

The present invention is to solve the above problems, an object of the present invention is to improve the shape of the lens installed inside the converter of the Raman laser device to prevent damage to the lens by the light reflected from the converter and methane gas It is to provide a Raman laser device to minimize the destruction of the.

1 is a view showing a converter installed in a conventional Raman laser device.

FIG. 2 is a diagram illustrating a refractive state and an image diameter forming state of a lens installed in a converting body of a conventional Raman laser device.

3 is a schematic diagram showing a configuration of a Raman laser device according to the present invention.

4 is a view showing a converter installed in the Raman laser device according to the present invention.

5 is a diagram illustrating a refractive state and an image diameter forming state of a lens installed in a converter of a Raman laser device according to the present invention.

** Description of the symbols for the main parts of the drawings *

100 ... total mirror

120 ... pump resonator

130 ... Partial reflector

140.Focus lens

150 ... collimating lens

200 ... Convert

The converter of the Raman laser device according to the present invention for achieving the above object is a chamber of which both ends are opened, the chamber is filled with methane gas, the lens of the laser device having a lens mounted inside the both ends of the chamber In the lens, the outer surface and the inner surface is formed convex with a predetermined curvature in the outward direction of the chamber.

And preferably the predetermined curvature of the outer surface of the lens is provided with 4.0mm-70.0mm.

In addition, the predetermined curvature of the inner surface of the lens is characterized in that the 5.0mm-500.0mm is provided.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the drawings.

Raman laser device according to the invention is a pump resonator 120 for generating a pulsed pumping laser light as shown in Figure 3, and converts the short wavelength laser light pumped by the pump resonator 120 to a long wavelength It is configured to include a converter (200).

Pump cavity (not shown) 120 is a flash lamp to generate the gain by exciting the amplifying medium is Nd-YAG rod (not shown) and, Nd ₃ ⁺ ion in Nd-YAG rod by illuminating the Nd-YAG rod And a Q installed between the total reflection mirror 100 and the partial reflection mirror 130, and the total reflection mirror 100 and the pump resonator 120, so that light having a wavelength of 1.064 μm among the light emitted from the Nd-YAG rod is resonated. A switching filter (110).

In addition, as shown in FIG. 4, the converter 200 induces Raman scattering of 1.064 μm short-wavelength laser light input from the pump resonator 120 and converts the laser light into long-wavelength laser light of about 1.54 μm. A chamber 210 filled with methane gas at a high pressure of the chamber 210, and a focusing lens 140 installed at the left end of the chamber 210 and focused at the right end of the chamber 210 to focus the incident light beams. It includes a collimating lens 150 for converting to parallel light.

Here, the focusing lens 140 and the collimating lens 150 are formed to be bent at a predetermined curvature in the outward direction of the chamber 210, and the curvature R _{1 of the} outer surface is about 4.0 mm to 70.0 mm. The curvature R _{2 on the} inner surface is approximately 5.0 to 500.0 mm.

Hereinafter, a description will be given of the operating state of the Raman laser device according to the present invention configured as described above, since the operating state of a typical Raman laser device is known, it will be briefly described and mainly the operating state of the lens.

The Raman laser device according to the present invention emits light from the pump resonator 120 when a high voltage is applied to the pump resonator 120. The emitted light resonates in the total reflection mirror 100 and the partial reflection mirror 130 to cause induction emission, and the induced emission light is amplified to emit a short wavelength of 1.064 μm through the second reflection mirror 130.

The light emitted through the induced emission proceeds to the converter 200 and is then scanned into the chamber 210 of the converter 200 through the focusing lens 140 of the converter 200. At this time, the emitted light injected into the chamber 210 is stimulated Raman scattering and stimulated brillouin scattering in the methane gas inside the chamber 210, the short wavelength of 1.064㎛ It is converted to a short wavelength of 1.54 mu m. The light converted to 1.54 μm long wavelength is emitted through the collimating lens 150.

On the other hand, the light incident to the converter 200 through the pump resonator 120 is incident to the outer surface of the initial focusing lens 140 as shown in FIG. 5 is refracted to the central portion of the focusing lens 140 and then again Proceeding to the inner surface of the focusing lens 140, the central portion of the focusing lens 140 is refracted in the outward direction, that is, in the direction opposite to the refractive direction on the outer surface.

As a result, the laser beam refracted from the focusing lens 140 has a smaller focusing angle θ ₂ than the conventional convex lens so that the focusing distance is relatively long, so that an image diameter I ₂ of the focused energy beam is obtained. The area of the image diameter becomes wider.

That is, the focusing density is approximately 4.0 GW / cm as in the present invention.²- 6.0GW / cm²When it is lowered to such a degree, it is possible to prevent methane gas destruction in the chamber 210 by the focusing beam, and the focusing part in the focusing lens 140 due to the reflection of the focusing beam is coated on the focusing lens 140. Since it is not concentrated on the surface, it is possible to prevent damage to the coating surface of the focusing lens 140.

In addition, since the area of the image diameter due to the reflected light is larger than that of the conventional collimating lens 140, the collimating lens 140 can exert the function of the focusing lens 140 to maintain the operation of the improved converter 200. To help.

Lenses installed in the converter of the Raman laser device according to the present invention as described above can increase the image diameter of the laser light emitted through the lens into the converter to reduce the focusing density to prevent methane gas destruction in the converter. It is possible to improve the operating life and efficiency of the device, and to minimize the damage to the lens.

Claims (3)

In the converter of the laser device having a chamber in which both ends are opened but the methane gas is filled therein, and a lens mounted inside the both ends of the chamber, The lens is a converter of the laser device, characterized in that the outer surface and the inner surface is formed convex with a predetermined curvature in the outward direction of the chamber. The converter of claim 1, wherein a predetermined curvature of the outer surface of the lens is set to 4.0 mm-70.0 mm. The converter according to claim 1, wherein the predetermined curvature of the inner surface of the lens is 5.0mm-500.0mm.