JPS5839388Y2 - photodetector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to provide an apparatus effective for detecting optical pulses.

Conventionally, in order to detect the peak output of temporally pulsed light such as Q-switched laser light, detection of the pulse half-width and total energy are usually measured separately using two different detectors. I'm looking for it.

Such a method brings about various inconveniences, mainly in the use of two detectors with different characteristics.

On the other hand, it is currently almost impossible to simultaneously detect the pulse half-width and total energy using one element.

The present invention provides an apparatus having a structure designed to relatively easily measure the half-width and total energy of such pulsed light, and will be described in detail below with reference to the drawings.

The photodetector according to the present invention has a pyroelectric effect and is formed from a pyroelectric detector using a transparent material suitable for the wavelength range of the light to be detected and a semiconductor photodetector made of silicon or other material with a small light-receiving area. be done.

FIG. 1 shows an embodiment of the photodetector according to the present invention, in which electrodes 3 are coated on both surfaces of a material 2 that is transparent to the detection pulse light 1 and is perpendicular to the direction of the polarization axis.

The electrode 3 is located at or near the center of the pyroelectric material 2.
A material that is opaque to the pulsed light 1 is used except for a portion 4 below about rrrm, and a transparent electrode or no electrode is attached to this light transmission aperture 4 portion.

Next, a semiconductor detector 6 is attached to the back surface of the light transmission aperture 4.

The semiconductor detector 6 has a p-0 junction made of silicon, for example, and has a very small chip area, with a light receiving area of 0.3
A size of about μm or less can be easily obtained.

FIG. 2 is a side view of the device according to the present invention shown in FIG. 1 from the light incident surface.

When the pulsed light 1 is incident on the photodetector having such a structure, it induces a temperature rise in the electroless material 2 and generates a pyrocurrent in the electric circuit system connected to the lead wire 5.

Generally, a pyroelectric detector has a slower response speed than a semiconductor detector, so in this case it is operated as a total energy detector.

When measuring the total energy using a pyroelectric detector according to the above method, the amount of light that passes through the light transmission aperture 4 must be smaller than the total amount of light. This can be achieved by reducing the optical power density incident on the surface in advance.

Next, at the same time, the semiconductor detector 6 detects temporal changes in the pulsed light 1.

For example, a photodetector using silicon has a fairly small minimum detection power as a photodetector, so it can operate even with a small amount of leakage light.

The output of the semiconductor detector 6 is set to externally detect the pulse half width through a lead wire 7.

It is practically convenient to use one photodetector mount in FIGS. 1 and 2, which are one embodiment of the present invention.

It is preferable that the semiconductor detector 6 be a chip-shaped solid pyroelectric detector.

Further, it is desirable that the light-receiving area of the electroless detector be as large as possible, but one of 1010×10 is usually sufficient.

As an example of the pyroelectric material 2, triglycine sulfate (TGS) is suitable for detecting visible light, and at present, a plate-like material with a size of 1010 x 10 can be easily manufactured.

The present invention has a structure in which a pyroelectric detector is made of a transparent non-electric material in the light wavelength range to be detected, a light transmission opening is provided, and a semiconductor photodetector is integrated into this. This is a photodetector characterized by being suitable for easily measuring the pulse half-width and total energy of pulsed light, and is not related to, for example, the material of the electrode 3 in FIG. 1.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the photodetector according to the present invention, and FIG. 2 is a front view thereof, in which 1 is the pulsed light to be detected, 2 is the pyroelectric material, 3 is the electrode, and 4 is the pulsed light to be detected. is a light transmission port, 5
6 indicates a lead wire, 6 indicates a semiconductor photodetector, and 7 indicates a lead wire.

Claims (1)

[Scope of utility model registration request] A light transmission aperture, which is much smaller than the light reception area of the non-electroelectric detector, is provided in a part of the plate-shaped pyroelectric detector, which has a sufficiently large light-receiving area, and a slight leakage of the detection light is passed through the light-transmission aperture with a high response speed. The photodetector has a structure integrated with the pyroelectric detector so that the semiconductor photodetector captures the total energy of the pulsed light by the pyroelectric detector, and the time response by the semiconductor photodetector. A photodetector characterized in that it measures simultaneously.