JPH01109783A - Spectroscope - Google Patents

Abstract

PURPOSE:To stabilize the optical path of an optical beam by constructing an optical element which separates and reflects the injected optical beam and the supporting member thereof, rotating means whose thermal contact with the supporting member is large and which allows the supporting member to rotate at a predetermined angle as the temperature changes. CONSTITUTION:Optical elements 3, 4 are inserted into a supporting member 2, the thermal contact between the optical elements 3, 4 and the supporting member 2 being made large. An optical beam is injected onto such optical elements 3, 4, separated and reflected, only the optical beam of a specific wavelength is returned along the original optical path. When the temperatures of the optical elements 3, 4 increase by the injection of the optical beam, changes in the temperatures are transferred to a rotating means 27 so that the supporting member 2 may be rotated at a predetermined angle in a direction offsetting the change in the optical beam path, whereby any changes in the temperatures of the optical elements 3, 4 allow the optical path of the diffracted optical beam having the specific wavelength to be stable along the original path after a predetermined time. According to the constitution, the optical path of the optical beam can quickly be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spectroscopic device used in a laser oscillation device such as an argon laser.

[Conventional technology]

BACKGROUND ART Conventionally, a spectroscopic device is known that separates a multi-wavelength light beam oscillated from a laser oscillation device such as an argon laser, and reflects a portion of the separated light beam so as to overlap the original light beam.

FIG. 4 is a partial configuration diagram of a conventional spectroscopic device 50 of this type.

The splitting device shown in FIG. 4 includes one triangular prism-shaped rhythm 51 made of quartz glass, a total reflection mirror 52 that reflects the light beam separated by the prism 51, and supports the prism 51 and the total reflection mirror 52. It includes a holder 53 and two types of screws 55 and 56 for attaching the holder 53 to the substrate 54. The screws 55 and 56 have different coefficients of thermal expansion; for example, the screw 55 is made of stainless steel, and the screw 56 is made of brass.

Brass has a higher coefficient of thermal expansion than stainless steel.

In the spectroscopic device 50 having such a configuration, when the laser-oscillated multi-wavelength light beam LB is incident on the prism 51, it is split into spectra and is incident on the total reflection mirror 52.

Of the separated light beams, the total reflection mirror 52 reflects only the light beam LBO of a specific wavelength that is perpendicularly incident on the total reflection mirror 52 along the optical path of the original light beam LB. This allows the light beam LBO of a specific wavelength to be superimposed on the original light beam LB.

By the way, when the temperature of the environment changes and the temperature of the prism 51 changes, the refractive index of the quartz glass forming the prism 51 changes in proportion to this change, and the optical path of the light beam separated by the prism 51 changes. When the temperature of the environment rises, the light beam separated by the prism 51 and reflected by the total reflection mirror 52 is bent more upward than that shown in FIG. As a result, the light beam superimposed on the original light beam LB is no longer the light beam LBO, but has a wavelength different from that of the light beam LBO. Such a change in the optical path of the light beam as the temperature rises is equivalent to rotating the holder 53 counterclockwise, so if the holder 53 is rotated clockwise as the temperature rises, Changes in the optical path of the light beam due to temperature rise can be offset. In the spectroscopic device shown in FIG. 4, when the temperature rises, the screw 56 stretches more than the screw 55, allowing the holder 53 to rotate clockwise. As a result, even if the temperature of the environment changes, only the light beam LBO of a specific wavelength can always be superimposed on the original light beam LB.

[Problem that the invention seeks to solve]

However, in the conventional spectrometer described above, the screw 55
．． Since the thermal contact between the prism 51.56 and the holder 53 is made only at these joints, the prism 51. The screws 55 and 56 do not reach a steady temperature until some time has passed after the total reflection mirror 52 is heated by the light beam and the temperature of the holder 53 has increased.Furthermore, the prism as an optical element and the total reflection mirror 52 are each separated. Since the optical elements are mechanically attached to the holder 53, their mutual angles tend to shift due to temperature changes, and there is a limit to making the entire optical element compact with a small heat capacity so that the temperature can quickly reach a steady state. . Furthermore, the holder 53 itself to which these optical elements are attached cannot be made smaller;
Furthermore, since it is difficult to increase the contact area with the optical element,
The holder 53 cannot quickly follow the temperature change of the optical element.As such, it takes a considerable amount of time for the temperature of the screws 55 and 56 to stabilize after the laser oscillation starts, and as a result, the spectrometer 9 is reflected. There is a problem in that it takes a considerable amount of time to bring the optical path of the light beam into a stable and optimal state.

The present invention provides a spectroscopy system that can quickly bring the optical path of a light beam into a stable and optimal state even if there is a temperature change in the optical element supported by the support member, that is, the holder, with the start of laser oscillation. The purpose is to provide equipment.

[Means for solving problems]

The present invention provides a single optical element that separates and reflects an incident light beam, a support member that supports the optical element with a large thermal contact, and a large thermal contact between the support member and the support member that is caused by temperature changes. The above-mentioned problems of the prior art are improved by a spectroscopic device characterized by comprising a rotation means for rotating at a predetermined angle.

[Effect]

In the present invention, a single optical element that separates and reflects a light beam is supported by a support member. For example, the optical element is fitted within the support member to increase thermal contact between the optical element and the support member. A light beam is made incident on an optical element, where it is separated and reflected, and, for example, only a light beam of a specific wavelength is caused to travel backward along the optical path of the original light beam. However, when the temperature of the optical element increases due to the incidence of the light beam, the refractive index of the optical element changes, so the optical path of the light beam of a specific wavelength changes and no longer follows the optical path of the original light beam. The temperature change of the optical element is transmitted to the rotating means via the supporting member, and the rotating means is caused to receive this temperature change, thereby rotating the supporting member by a predetermined angle in a direction that offsets the change in the optical path of the light beam. As a result, even if the temperature of the optical element changes, after a predetermined period of time, the optical path of the separated light beam of a specific wavelength becomes stable along the optical path of the original light beam. By the way, in the present invention, the thermal contact between the single optical element and the support member is increased, and the thermal contact between the support member and the rotating means is also increased, so that the temperature change of the optical element is reflected by the rotation through the support member. The time it takes to transmit the temperature to the rotating means and bring the rotating means to a steady temperature can be significantly shortened. This allows the optical path of the light beam to be quickly stabilized.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a configuration diagram of an embodiment of a spectroscopic device according to the present invention, and FIG. 2 is a schematic perspective view of the spectroscopic device attached to an angle adjustment device. Referring to FIG. 1, in the spectroscopic device 1 of this embodiment, the prism section 3 is fitted into a hole 68 formed in a support member or holder 2 made of aluminum alloy. The prism section 3 is made of quartz glass, and a mirror 4 is attached to the rear end of the prism section 3 perpendicularly to the traveling direction of light within the prism section 3. Mirror 4 is
For example, a dielectric multilayer IIa formed directly on the prism part 3
, and is designed to reflect most of the light beam that enters it.

The prism part 3 to which such a mirror 4 is attached has a cushion 5 made of Teflon. It is firmly fixed in the holder 2 by a pressurized metal 6° screw 7 and is in contact with the holder 2 over a large area. In addition, cushion 5. A hole with a diameter of about 4 mm is drilled in the center of the pressure metal H36 and the screw 7, and by observing the slight light beam that passes through the mirror 4 through the window 30, the spectrometer l can be installed from the outside to determine its condition. can be adjusted. That is, by mechanically rotating the holder 2 using the angle adjustment device 27, the angle between the prism section 3 inside the holder 2 and the laser tube 20 can be adjusted.

Further, the holder 2 is provided with a through hole 10 that makes a predetermined angle with the front surface 9 of the hole 8 for allowing a light beam to enter and exit the prism portion 3 .

Further, referring to FIG. 2, the holder 2 has an aluminum alloy protrusion 11 on the lower side on the side to be attached to the substrate 22 of the angle adjustment device 27, and a part of the temperature compensating member 12 on the upper side. is embedded. The protrusion 11 is preferably integrated with the holder 2, and the temperature compensating member 1
2 is made of, for example, quartz glass, and its shape is, for example, 3.
It is a rectangular parallelepiped with dimensions of 7.5 x 7.5 am. Holder 2
The part of the temperature compensating member 12 that is fitted into the holder 2
It has a wide contact area. sand.

That is, in FIGS. 1 and 2, both sides 1 of the temperature compensating member 12
3,14. Bottom surface 15. End surface 16 is in contact with holder 2. Note that the temperature compensating member 12 protruding from the holder 2
It is assumed that the cross-sectional shape and cross-sectional area of the portion and the protrusion 11 are almost the same, and the distance between the temperature compensating member 12 and the protrusion 11 is 17rIm.

FIG. 3 is a schematic configuration diagram of a laser oscillation device using the spectroscopic device 1 having such a configuration. In the laser oscillator shown in FIG. 3, for example, an argon laser that outputs light with multiple wavelengths is used as the laser tube 20, and the multiple wavelength light beams from the laser tube 20 are separated and reflected to select a light beam with a specific wavelength. The spectroscope 1 is operated to overlap only the original light beam with the original light beam, and only the light beam of a specific wavelength is repeatedly sent back and forth between the spectroscope 1 and the output mirror 21. It is designed to oscillate only the beam.

In such a laser oscillation device, the spectroscopic device 1 has a first
As shown in the figure, it is attached to the substrate 2'2 of the angle adjustment device 27 with screws 24 via a ceramic heat insulating member 23. That is, the screw 24 penetrates the heat insulating member 23 from the side of the board 22 and is screwed into the holder 2, and the spring 25 urges the board 22 toward the holder 2. This allows the protrusion 11 of the holder 2 and the temperature compensating member 12 to firmly contact the substrate 22, while the holder 2. Projection 11. The holder 2 can be rotated with respect to the substrate 22 when the temperature compensating member 12 expands and contracts due to temperature changes.

Such a spectrometer Tt1 is connected to an argon laser laser tube 2.
The operation when applied to 0 will be explained next.

The spectrometer 'f11' is set so that the light beam of the blazing wavelength from the laser tube 20 is separated, and only the light beam with a wavelength of, for example, 5,145 is superimposed on the original light beam and travels backwards.

In other words, the wavelength 5 of the prism part 3 made of quartz glass
Since the refractive index for the light beam of 145 people is 1.461, the Brewster angle is 55.61°, and the wavelength is 5145 degrees.
The angle adjusting device 27 is adjusted so that the light beam enters the prism section 3 at this Brewster angle, and the spectroscopic device 1 is placed relative to the laser tube 20. As a result, the light beam of 5145 wavelengths incident on the prism section 3 is hardly reflected on the surface of the prism section 3, is bent with a refractive index of 34.39 degrees, and travels inside the prism section 3 perpendicularly to the mirror 4. It is incident, is reflected vertically, travels back along the original optical path, and overlaps the original optical beam. On the other hand, a light beam of other wavelengths, for example a light beam of wavelength 4880A, has a refractive index of 34.
Since it enters the prism part 3 at an angle of 31 degrees and does not enter the mirror 4 perpendicularly, the light beam of wavelength 4880 reflected by the mirror 4 does not proceed along the original optical path and does not overlap with the original light beam. .

In this way, the spectroscopic device 1 can reflect only the light beams of 5145 specific wavelengths out of the separated light beams along the original optical path. Only a light beam with a wavelength of 5145 people can repeatedly travel back and forth between the output mirror 21 and the output mirror 21, and this can be output from the output mirror 21.

By the way, after the laser oscillation starts, the prism part 3 and the mirror 4 are heated by the incident light beam, and the refractive index of the prism part 3 changes. Since the temperature coefficient of the refractive index of quartz glass is 1.0xlO'/'C, the optical path of the reflected light beam changes with a temperature coefficient of 2.0x10-5 radian/°C as the refractive index of the prism section 3 changes. It shifts. This causes the wavelength 5145 that was originally reflected along the original optical path to be
The person's light beam no longer follows the original optical path.

On the other hand, the prism section 3. The temperature change of the mirror 4 is quickly transmitted to the holder 2 which is in contact with the mirror over a wide area, and the holder 2 is moved to the prism part 3 . The temperature is changed to the same as that of mirror 4. As a result, the holder 2's own tree, the protrusion 11 of the holder 2. The temperature compensating member 12 fitted into the holder 2 also expands, but the holder 2 and the protrusion 11 of the holder 2 are made of aluminum alloy, and the temperature compensating member 12 is made of quartz glass, each having a different coefficient of thermal expansion of 23×10.
/'C,0,4X10'/'C, so for the temperature compensation member 12 of length 1, the part of the holder 2 corresponding to this length 1 (length j-h part), The protrusion 11 (length h) extends more. Therefore, due to the temperature rise, the spectroscope 1 rotates clockwise with respect to the substrate 22 of the angle adjustment device 27 at an angle determined by the difference in these elongations, and the optical path of the light beam due to the change in the refractive index of the prism section 3 is changed. This offsets the shift, allowing the wavelength 5145 second light beam to continue along the original optical path even if the temperature changes.

Note that the prism section 3. After the temperature of the mirror 4 changes, a predetermined time is required until the spectroscope 1 rotates by a predetermined angle with respect to the laser tube 20 to compensate for this temperature change. Since the temperature compensating member 12 has a wide contact area with the holder 2, the temperature compensating member 12 has a large contact area with the holder 2. Projection 11. Temperature compensation member 1
The time it takes for the spectroscopic device 1 to reach a steady temperature is short, and the spectroscopic device 1 can be rotated quickly.

Furthermore, in this embodiment, since the mirror 4 is formed on the prism section 3, the prism section 3. The mirror 4 can be made small and has a small heat capacity.
The holder 2 itself can also be made small and have a small heat capacity. As a result, the prism section 3. It becomes possible to transmit the temperature change of the mirror 4 to the protrusion 11 and the temperature compensating member 12 more quickly. Note that the prism section 3 as an optical element. Since the mirror 4 is constructed as a single unit, there is no angular deviation between them due to temperature changes.

When the conventional spectroscopic device 50 as shown in FIG. Using I11, stable laser light could be obtained within 15 minutes.

In the above-described embodiment, the spectrometer 1 is used in a laser oscillation device, splits the light beam incident on the spectrometer 1, reflects the light beam of a specific wavelength along the optical path of the original light beam, and reverses the light beam. Although it has been explained that it is designed to direct a light beam of a specific wavelength from an incident light beam in a predetermined direction (
It can also be used in applications where the light beam is simply extracted in a direction different from the optical path of the original light beam.

Further, in the above-described embodiment, the protrusion 11. Temperature compensation member 12
Although the shape, size, etc. are specified using specific numerical values, various modifications can be made without being limited to these numerical values.

Furthermore, in the above embodiment, the thermal contact between the temperature compensating member 12 and the holder 2 is large, but the holder 2
In other words, quartz glass has a particularly small coefficient of thermal expansion compared to aluminum alloy, so even if heat is not transmitted to the temperature compensation member 12, there is no difference in the rotation of the spectrometer 1. It does not affect the protrusion 11
The spectroscopic device 1 can be rapidly rotated by the rapid expansion and contraction of. Further, the protrusion 11 does not have to be integral with the holder 2, but even in that case, it is necessary to increase the thermal contact with the holder 2.

〔Effect of the invention〕

As explained above, according to the present invention, a single optical element is supported by the support member with a large thermal contact, and the thermal contact between the support member and the rotating means is increased, so that the temperature of the optical element changes. can be transmitted to the rotating means extremely quickly, and the optical path of the light beam can be quickly brought into a stable and optimal state.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of a spectroscopic device according to the present invention, Fig. 2 is a perspective view of the spectroscopic device from the side where it is attached to an angle adjustment device, and Fig. 3 is a diagram of a laser oscillation device using the spectroscopic device. A schematic configuration diagram, FIG. 4, is a configuration diagram of a conventional spectroscopic device. DESCRIPTION OF SYMBOLS 1... Spectroscope, 2... Support member (holder), 3...
... Prism part, 4... Mirror, 11... Protrusion part,
12...Temperature compensating member patent applicant Masaharu Uemoto Representative Hamamatsu Photonics Co., Ltd. Patent attorney Figure 2

Claims (1)

[Claims] 1) A single optical element that separates and reflects an incident light beam, and a support member that supports the optical element with large thermal contact;
A spectroscopic device comprising a rotation means that has a large thermal contact with the support member and rotates the support member at a predetermined angle due to a temperature change. 2) The optical element includes a prism portion and a dielectric multilayer mirror formed on the prism portion, and is fitted to the support member. The spectroscopic device described. 3) The rotating means has a temperature compensating member attached to the supporting member, and a protruding portion provided at an end opposite to the temperature compensating member and having a large thermal contact with the supporting member, and the protruding portion has a temperature compensating member attached to the supporting member. 2. The spectroscopic device according to claim 1, wherein the spectroscopic device has a coefficient of thermal expansion larger than that of the temperature compensating member.