JP2010186762A - Solid-state laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a calorific value of an acoustooptical element driving circuit. <P>SOLUTION: A solid-state laser apparatus 10 initiates the drive of an acoustooptical element 4 at the same time or substantially the same time as that of the drive initiation of a semiconductor laser 1 to enlarge the loss of a resonator 6, and terminates the drive of an acoustooptical element 4 at a timing according to a lifetime T of fluorescence of a solid laser medium 3 to minimize the loss of a resonator 6. Thus, the time for driving an acoustooptical element 4 is short, so that the calorific value of an acoustooptical element driving circuit 8 can be suppressed and it becomes not necessary to attach a large dissipating component to the acoustooptical element driving circuit 8. In addition, the time for feeding an acoustooptical element driving RF signal R is short, so that the ectromagnetic interference EMI can be suppressed. The temperature rise of circuit components such as capacitor and coil can be suppressed and output stability can be enhanced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid-state laser device, and more particularly to a solid-state laser device that outputs a pulse laser using an acousto-optic element.

A solid-state laser device using an acousto-optic element is known (see Patent Document 1).
In this solid-state laser device, the acousto-optic element is driven to increase the resonator loss, and the semiconductor laser starts to be driven. Then, when the gain of the resonator becomes sufficiently high, the driving of the acoustooptic device is stopped to rapidly reduce the loss of the resonator, and the energy stored in the solid laser medium is taken out as a pulse laser output. After outputting the pulse laser, the driving of the semiconductor laser is stopped and the acoustooptic device is driven again. This operation is repeated.

JP 05-198870 A ([0036])

In the conventional solid-state laser device, the acoustooptic device is driven almost continuously except for a short time when the pulse laser is output. For example, if the pulse repetition frequency is 300 Hz and the driving stop time of the acoustooptic device is about 0.01 ms, the acoustooptic device is driven for about 99.7% during the operation time.
However, since the amount of heat generated by the acoustooptic device drive circuit is increased by driving the acoustooptic device substantially continuously, it is necessary to attach a large heat dissipation component to the acoustooptic device drive circuit.
SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state laser device that suppresses the amount of heat generated by an acoustooptic device drive circuit and eliminates the need to attach a large heat dissipation component to the acoustooptic device drive circuit.

In a first aspect, the present invention provides a semiconductor laser (1) that generates pulsed laser light that is pulse-driven, a solid-state laser medium (3) that is excited by the excitation laser light, and the solid-state laser medium (3). An acoustooptic device (4) installed in a resonator (6) formed to control the loss of the resonator (6), and all or part of a period in which the semiconductor laser (1) is not driven The solid-state laser device (10) is provided with acoustooptic device drive control means (8, 9) that does not drive the acoustooptic device (4).
In the solid-state laser device (10) according to the first aspect, since the acoustooptic device (4) is not driven during all or part of the period during which the semiconductor laser (1) is not driven, the amount of heat generated by the acoustooptic device drive circuit. Is suppressed, and there is no need to attach a large heat dissipation component to the acoustooptic device drive circuit.
In a second aspect, the present invention provides that the acoustooptic device drive control means (8, 9) does not drive the semiconductor laser (1) within a period during which the semiconductor laser (1) is driven. The solid-state laser device (10) according to claim 1, wherein the acoustooptic device (4) is driven for a period corresponding to the fluorescence lifetime (T) of the solid-state laser medium (3) in all or part of the period. )I will provide a.
In the above configuration, the fluorescence lifetime (T) is the time required for the fluorescence intensity to decrease to 1 / e.
In the solid-state laser device (10) according to the second aspect, the acousto-optic element (4) starts to be driven at the same timing or almost the same timing as the driving of the semiconductor laser (1), and the solid-state laser medium (3) The driving of the acousto-optic device (4) is stopped at a timing that matches the fluorescence lifetime (T). According to this, for example, when the pulse repetition frequency is 300 Hz and the fluorescence lifetime (T) of the solid-state laser medium (3) is about 0.2 ms, the acoustooptic device is driven by about 6% during the operation time. Become. For this reason, the heat generation amount of the acoustooptic device drive circuit is suppressed, and it is not necessary to attach a large heat dissipation component to the acoustooptic device drive circuit.
Since the semiconductor laser drive is stopped after the pulse laser is output, the gain of the resonator becomes 0, and laser oscillation does not occur even if the acoustooptic device is not driven.

  According to the solid-state laser device of the present invention, the heat generation amount of the acoustooptic device drive circuit can be suppressed. Therefore, it is not necessary to attach a large heat radiating component to the acoustooptic device drive circuit.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

Example 1
FIG. 1 is an explanatory diagram illustrating a solid-state laser device 10 according to the first embodiment.
The solid-state laser device 10 includes a semiconductor laser 1 that generates excitation laser light, a lens 2 that collects the excitation laser light, a solid-state laser medium 3 that is excited by the excitation laser light, and a solid-state laser medium 3. An acoustooptic device 4 that controls the loss of the resonator 6, a mirror 5 that forms the resonator 6 between the solid-state laser medium 3, and a semiconductor laser drive circuit 7 that supplies an LD drive current I to the semiconductor laser 1. An acoustooptic device drive circuit 8 that supplies the acoustooptic device driving RF signal R to the acoustooptic device 4, and a control unit 9 that controls the supply timing of the drive current I, the supply timing of the acoustooptic device drive RF signal R, and the like. It has.

FIG. 2 is a time chart showing the operation timing of the solid-state laser device 10.
The LD drive current I is supplied, for example, at a pulse repetition frequency f = 300 Hz and a pulse width τ = about 0.22 ms.
The acoustooptic device driving RF signal R is started to be supplied, for example, earlier than the supply start time t1 of the LD drive current I by a margin time Δ, and the fluorescence lifetime T of the solid-state laser medium 3 has elapsed from the supply start time t1 of the LD drive current I. The supply is stopped later. For example, if the margin time Δ is 0.1 ms and the fluorescence lifetime T of the solid-state laser medium 3 is about 0.2 ms, the pulse width T + Δ of the acoustooptic device driving RF signal R is about 0.3 ms.
The loss L of the resonator 6 increases at the same timing as the acoustooptic device driving RF signal R.
The gain G of the resonator 6 increases from the supply start time t1 of the LD drive current I, and becomes the highest after the fluorescence lifetime T of the solid-state laser medium 3 has elapsed from the supply start time t1 of the LD drive current I, and drives the acoustooptic device. It becomes low when the supply of the RF signal R is stopped, and becomes 0 after the supply stop time t3 of the LD drive current I.
The pulse laser output is output immediately after the supply of the acoustooptic device driving RF signal R is stopped.

FIG. 3 is a temperature characteristic diagram showing the operating time of the solid-state laser device 10 and the temperature change of the heat radiation fin of about 1.4 K / W attached to the acoustooptic device drive circuit 8.
The operating conditions are a pulse repetition frequency f = 300 Hz, a pulse width T + Δ of the acoustooptic device driving RF signal R = about 0.3 ms, and a power of the acoustooptic device driving RF signal R of about 7 W.
It was found that the temperature hardly increased.

FIG. 4 is a time chart showing a case where the solid-state laser device 10 is controlled at the conventional operation timing.
The LD drive current I is supplied, for example, at a pulse repetition frequency f = 300 Hz and a pulse width τ = about 0.22 ms.
The acousto-optic device driving RF signal R is supplied substantially continuously except that the supply is stopped from the supply start time t1 of the LD drive current I after the lapse of the fluorescence lifetime T of the solid-state laser medium 3 to immediately after the pulse laser output. .
The loss L of the resonator 6 increases at the same timing as the acoustooptic device driving RF signal R.
The gain G of the resonator 6 increases from the supply start time t1 of the LD drive current I, and becomes the highest after the fluorescence lifetime T of the solid-state laser medium 3 has elapsed from the supply start time t1 of the LD drive current I, and drives the acoustooptic device. It becomes low when the supply of the RF signal R is stopped, and becomes 0 after the supply stop time t3 of the LD drive current I.
The pulse laser output is output immediately after the supply of the acoustooptic device driving RF signal R is stopped.

FIG. 5 shows the operating time of the solid-state laser device 10 when the solid-state laser device 10 is controlled at the conventional operation timing and the temperature change of the heat radiation fin of about 1.4 K / W attached to the acoustooptic device drive circuit 8. It is a temperature characteristic figure.
The operating conditions are a pulse repetition frequency f = 300 Hz, an acoustooptic device driving RF signal R supply stop time of about 0.01 ms, and an acoustooptic device driving RF signal R power of about 7 W.
The temperature has risen significantly.

According to the solid-state laser device 10 of the first embodiment, the following effects can be obtained.
Since the time for supplying the acoustooptic device driving RF signal R is short, the amount of heat generated by the acoustooptic device drive circuit 8 can be suppressed. Therefore, it is not necessary to attach a large heat radiating component to the acoustooptic device drive circuit 8.
-Since the time for supplying the acoustooptic device driving RF signal R is short, electromagnetic interference (EMI) can be suppressed.
Since the amount of heat generated by the acoustooptic device drive circuit 8 can be suppressed, the temperature rise of circuit components such as capacitors and coils can be suppressed. Therefore, output stability can be improved.

  The solid-state laser device of the present invention can be used in the bioengineering field and the measurement field.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory diagram illustrating a solid-state laser device according to a first embodiment; 3 is a time chart showing the operation timing of the solid-state laser apparatus according to Example 1. 3 is a temperature characteristic diagram of the solid-state laser apparatus according to Example 1. FIG. It is a time chart which shows the conventional operation timing. It is a temperature characteristic figure of the solid-state laser apparatus concerning the conventional operation timing.

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Lens 3 Solid laser medium 4 Acoustooptic device 5 Mirror 6 Resonator 7 Semiconductor laser drive circuit 8 Acoustooptic device drive circuit 9 Control part 10 Solid state laser apparatus

Claims (2)

A semiconductor laser (1) that generates pulsed laser light by being driven by a pulse, a solid laser medium (3) that is excited by the pump laser light, and a resonator (6) that includes the solid laser medium (3). The acousto-optic device (4) that is installed inside and controls the loss of the resonator (6), and the acousto-optic device (4) is driven during all or part of the period during which the semiconductor laser (1) is not driven. A solid-state laser device (10) characterized by comprising acoustooptic device drive control means (8, 9). During the period in which the semiconductor laser (1) is being driven, the acoustooptic device drive control means (8, 9) is configured to perform the acoustooptic operation in all or part of the period in which the semiconductor laser (1) is not driven. The solid-state laser device (10) according to claim 1, characterized in that the element (4) is driven for a period corresponding to the fluorescence lifetime (T) of the solid-state laser medium (3).

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