JPH0794819A - Laser element - Google Patents

Abstract

PURPOSE:To provide a compact laser element which can oscillate (emit light) from an infrared ray wavelength region to an ultraviolet ray wavelength region. CONSTITUTION:The title element is provided with a laser resonator where a dot-shaped region 1 whose refractive index differs from that of a peripheral part at least in one-dimensional direction is laid out at a pitch of 1mum or less and which propagates light with a specific wavelength partially and a light emitting part 2 for emitting light at a specific wavelength which is laid out at a specific position in one-dimensional direction of the laser resonator.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to laser devices.

[0002]

2. Description of the Related Art Laser light is widely put to practical use, for example, for measurement, communication, or for processing and heat sources. As this type of laser light source, solid-state lasers such as visible light ruby laser, infrared YAG laser and YLF laser, gas lasers such as visible light Ar laser and ultraviolet light nitrogen laser are generally well known. ing. In addition, with the development of semiconductor technology, infrared GaAs semiconductor lasers have been developed, and laser devices (laser light oscillators) have been greatly downsized.

By the way, in order to increase the information density in the application of laser light, for example, in the case of optical recording, it is desired to shorten the wavelength of the light source. Recently, the semiconductor laser is also changed from the infrared light region to the visible light region. And shorter wavelengths are being promoted. For example, with a ZnSe-based semiconductor laser, oscillation up to around 450 nm is about to be put to practical use. Here, if it is possible to realize oscillation in the infrared light region to the ultraviolet light region with a small laser, the information density when performing the optical recording or the like can be further greatly improved. It becomes possible to easily make it compact.

[0004]

However, the only semiconductor lasers that can be miniaturized are the GaAs semiconductor lasers and the ZnSe semiconductor lasers, and the small lasers that oscillate in the ultraviolet region are still unknown. Has not been done. In other words, a small laser that oscillates at a wavelength of 450 nm or less has not been realized yet, with great expectations for practical use.

In view of the above points, an object of the present invention is to provide a small-sized laser element which is inexpensive and can oscillate (emits) in the infrared light wavelength region to the ultraviolet light wavelength region.

[0006]

In a laser device according to the present invention, point-like regions having a refractive index different from that of a peripheral portion in at least one dimension are arranged at a pitch of 1 μm or less and partially propagate light having a predetermined wavelength. And a light emitting unit which emits light at a predetermined wavelength and is arranged at a predetermined position in the one-dimensional direction of the laser resonator.

The present invention will be described in detail below. In recent years, when point-like gratings having a certain pitch are periodically present, a wave having a wavelength about the same as the pitch of the grating is diffracted. The study focused on the fact that the wavelength of standing waves that can exist in the region is limited, and that the electrons in metals and semiconductors are limited by the periodicity of the crystal lattice, and that the standing waves are limited by the formation of a band structure. Is being promoted. That is, a band structure in which electromagnetic waves in the visible light wavelength region are used instead of electron waves is formed by forming a dot-shaped region having a refractive index different from that of the peripheral portion in a grid pattern at a pitch of about the wavelength of visible light. , So-called photonic bands are actively researched, and experiments with microwaves and millimeter waves are also known.

[0008] The inventors of the present invention focused on the research of the photonic band, and further, when applying the VLSI technology, it is possible to form a grating with an extremely small pitch up to sub μm. We have found that it is possible to realize a photonic band from the visible light region to the ultraviolet light region, and that light with a wavelength corresponding to the band gap is reflected by the band formed by such a periodic grating. It was Furthermore, as a result of further research based on such knowledge, the above-mentioned dot-shaped region is at least one-dimensionally oriented.
The inventors have found that when the pitch is 1 μm or less, light of a predetermined wavelength is partially propagated in the one-dimensional direction, and the present invention has been accomplished.

In the present invention, the light emitting portions may be arranged in the central portion of the arrangement of the dot-like regions arranged at a pitch of 1 μm or less so that light of a predetermined wavelength is partially propagated in both one-dimensional directions. However, the light emitting portion may be arranged near the end of the array of dot-like regions, and the dot-like regions may be arranged on the side opposite to the array of dot-like regions where light of a predetermined wavelength does not propagate and is reflected. . Further, the oscillation threshold can be reduced by using a lattice structure in which the electromagnetic wave wavelength does not propagate in the two-dimensional direction or the three-dimensional direction with respect to the one-dimensional direction in which the light of the predetermined wavelength partially propagates. In this case, the lattice array may be, for example, a body-centered cubic lattice or a face-centered cubic lattice, and the lattice points may be in the form of a sphere, a regular tetrahedron, a regular octahedron, a regular dodecahedron, or the like.

In the present invention, a laser element which oscillates ultraviolet light can be easily formed particularly by using polysilane as a material. That is, polysilane has a high-sensitivity photosensitizer, and the exposed area is siloxane-ized to have a refractive index of
Since it changes by about 0.3, it is possible to easily form the grating at a pitch of about the wavelength of visible light to ultraviolet light. Moreover, since polysilane emits light in the vicinity of 340 nm, it can serve as a light emitting portion itself and function as a small ultraviolet laser. When polysilane is used as the material, it is not necessary to insert the light emitting portion at a predetermined position of the lattice to be the laser resonator as described above, but for example, Nd ³⁺ : Y ₃ Al ₅ O ₁₂ Glass, AlAs semiconductors and SeZn semiconductors,
Depending on the form in which various dye-based luminescent materials are doped,
The light emitting portion may be formed and attached at a predetermined position. At this time, the material for the grating to be the laser resonator is not particularly limited to polysilane, and the grating can be formed in the same manner as long as the material has photosensitivity and the refractive index changes in the exposed portion. it can.

In the above laser resonator, a point-like region (lattice point) with respect to the wavelength λ of light partially propagated.
The pitch P may be a positive multiple of λ / 2 (1 μm or less), and the size of the diameter may be P / 10 or more and 9 · P / 10 or less, and the dot-like regions may be arranged. Further, the number of arranged dot-shaped regions is about 10 cycles or more in the one-dimensional direction in which light partially propagates, and the difference in refractive index between the dot-shaped regions and the peripheral portion may be 0.1 or more.

[0012]

According to the laser element of the present invention, the dot-like regions (lattice points) forming a so-called photonic band are
Since it functions as one type of wavelength selection mirror, the wavelength and reflectance to be selected can be set arbitrarily by changing the number of arranged dot-shaped regions, the pitch interval, and the like.
Then, when the light emitting portion arranged at a predetermined position between the dot-like regions (lattice points) arranged in the one-dimensional direction is excited by light or current to form an inverted distribution state, the dot-like regions serve as resonator mirrors. Then, the laser light is oscillated in the resonance direction. On the other hand, when the laser light oscillates in the resonance direction, the periphery (two-dimensional direction or three-dimensional direction) of the laser light is arranged in a dot-shaped region in which the propagation of the electromagnetic wave wavelength is suppressed. Will be easier to pick up. In other words, the spontaneous emission light emission in the two-dimensional direction and the like is reduced, and the oscillation threshold value is significantly lowered, so that a stable laser function is maintained and exhibited.

[0013]

EXAMPLES Examples of the present invention will be described below with reference to FIGS. 1 (a) and 1 (b).

FIG. 1 (a) is a cross-sectional view showing an example of the essential structure of a laser device according to the present invention, which is made of polysilane and forms a cube of 10 μm square. In this configuration example, a dot-shaped area (lattice point) array 1 arranged in the three-dimensional direction
In a, 1b, 1c, 1e, 1f, 1g, etc., the interval (pitch) of each dot-like area (lattice point) 1 is constant, while in dot-like area (lattice point) array 1d, dot-like area (lattice point) The interval (pitch) of 1 is the dot-like region (lattice point) array 1a, 1b, 1
It is different from the case of c, 1e, 1f, 1g, etc. That is, in the dot-like region (lattice point) array 1d, the interval (pitch) of the dot-like region (lattice point) 1 is partially set to be small, and the predetermined interval between the dot-like region (lattice point) array 1d is set. The configuration is such that the light emitting unit 2 is arranged at the position.

The structure of the above laser device will be described more specifically together with its manufacturing process. First, the following [Chemical formula 1] will be given.
Polysilane (molecular weight 200,000), whose general formula is shown in Fig. 1, is formed on the supporting substrate by the LB method (Langmuir Brodgett method).
A film with a thickness of 0.6 μm is formed, and the entire surface is irradiated with ultraviolet rays to form siloxane.

[0016]

[Chemical 1] Then, a 0.1 μm-thick polysilane layer is laminated and formed by the LB method, and when this polysilane layer is selectively exposed, the exposed part becomes siloxane, while the unexposed part is 0.1 μm.
The angular dot-like regions (lattice points) 1 are formed, and the dot-like region (lattice point) array 1a is formed at 0.7 μm intervals (pitch). Thereafter, a polysilane layer having a thickness of 0.6 μm is similarly laminated and formed on the surface of the dot-shaped region (lattice point) array 1a, and the entire surface is irradiated with ultraviolet rays to form a polysilane layer having a thickness of 0.1 μm. By stacking and forming a film, and selectively exposing this polysilane layer, the exposed area becomes siloxane while the unexposed area is 0.1 μm.
The angular dot-like regions (lattice points) 1 are formed, and the dot-like region (lattice point) array 1b is formed at 0.7 μm intervals (pitch) similar to the dot-like region (lattice point) array 1a. Thereafter, the same process is repeated to form a six-layer array of dot-like regions (lattice points) on the supporting substrate. In the figure, 1b indicates a dot-like area (lattice point) array on the fifth layer, and 1c indicates a dot-like area (lattice point) array on the sixth layer.

Next, a polysilane layer having a thickness of 0.6 μm is similarly laminated and formed on the surface of the dot-shaped region (lattice point) array 1c, and the surface other than the region which becomes the light emitting portion 2 is exposed to ultraviolet rays. Irradiation is performed, and a polysilane layer having a thickness of 0.1 μm is laminated and formed, and this polysilane layer is selectively exposed. At this time,
As shown in plan view in FIG. 1 (b), in a predetermined direction (leftward in FIG. 1 (b)) with respect to the light emitting section 2 having an outer diameter of about 1 μm, a dot-like region (lattice point) of 0.1 μm angle 1 are arranged in a one-dimensional direction at 0.66 μm intervals (pitch). Then, a polysilane layer having a thickness of 0.6 μm is laminated and formed on the 1d surface of the dot-shaped region (lattice point) array, and the surface other than the region to be the light emitting portion 2 is irradiated with ultraviolet rays to be silicified. . In addition, the steps of laminating and forming a 0.1 μm thick polysilane layer and selectively exposing this polysilane layer, and the step of laminating and forming a 0.6 μm thick polysilane layer and irradiating the entire surface with ultraviolet rays. Repeatedly, a six-layer array of dot-like regions (lattice points) is sequentially formed on the light emitting portion 2 to obtain a laser device including a hexagonal crystal lattice of 10 μm square.

In the light emitting section 2 of the laser device having the above-mentioned structure, when a light having a pulse width of 5 nsec and a wavelength of 337 nm was excited by a nitrogen laser, a required laser oscillation was exhibited in an ultraviolet light region wavelength. That is, the light emission part 2 was excited by the nitrogen laser, and the light emission in each direction from the dot-shaped region (lattice point) 1 was collected and observed by the light receiver. As a result, the excitation output was increased from 10 μW to 10 mW. Along with this, it was confirmed that the full width at half maximum of the emission peaking at a wavelength of 350 nm narrowed from 20 nm to 5 nm, and the decay time constant increased from 20 nsec to 4 nsec, causing laser oscillation.

Although the case where the laser element is made of polysilane as a material has been exemplified here, the present invention is not limited to this, and a lattice can be formed by using another material which can also be finely processed. You may form. Further, in order to prevent the electromagnetic wave wavelength from propagating in the two-dimensional direction or the three-dimensional direction with respect to the one-dimensional direction in which light of a predetermined wavelength partially propagates, in the above, a grating having a different pitch only in the one-dimensional direction around the light emitting portion is used. Although the structure is adopted, the point is that light propagation in directions other than the one-dimensional direction should be suppressed / prevented. The light refraction index may be different so that the above light does not propagate.

[0020]

As described above, according to the laser element of the present invention, the population inversion state is easily formed by exciting the light emitting portion, and the point region becomes a resonator mirror to cause resonance. Since it oscillates laser light in the direction,
It works effectively as a small laser.

[Brief description of drawings]

1A is a cross-sectional view showing a configuration example of a main part of a laser device according to the present invention, and FIG. 1B is a point where light of a predetermined wavelength is partially propagated in the configuration example of a main part of FIG. 1A. FIG.

[Explanation of symbols]

1 ... Point-like regions (lattice points) 1a, 1b, 1c, 1d, 1e, 1f,
1g ... Array of dots (lattice points) 2 ... Light emitting part

Claims (2)

[Claims] 1. A laser resonator in which point-like regions having a refractive index different from that of a peripheral portion in at least a one-dimensional direction are arranged at a pitch of 1 μm or less, and partially propagate light of a predetermined wavelength, and a primary of the laser resonator. A laser device, comprising: a light emitting section which is disposed at a predetermined position in the original direction and emits light at a predetermined wavelength. 2. The laser device according to claim 1, wherein the dot-shaped region and the light emitting portion are made of polysilane.