Reflection prevention film and optical component having the same

Abstract

To provide a reflection prevention film with high resistance to a laser beam.SOLUTION: A reflection prevention film 10 is provided in a manner to cover a light incident and / or emission surface of an optical component 20 for a laser beam with a wavelength λ. The reflection prevention film 10 includes a film body 11 and an undercoat layer 12 laid on the side of the optical component 20. The optical film thickness of the undercoat layer 12 is less than λ / 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an antireflection film and an optical component provided with the same. [Background technology]

[0002] 2. Description of the Related Art For the purpose of increasing the light transmittance of optical components such as lasers, optical fibers, and lenses, antireflection films are provided so as to cover the light entrance surfaces and light exit surfaces of the components (eg, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5362256 Summary of the Invention [Problem to be solved by the invention]

[0004] As the output of lasers increases, the possibility of damage to anti-reflection coatings provided on optical components for laser light increases.

[0005] An object of the present invention is to provide an anti-reflection film that is highly resistant to laser light. [Means for solving the problem]

[0006] The present invention provides an anti-reflection film that is provided to cover a light entrance surface and / or a light exit surface of an optical component for laser light of wavelength λ, the anti-reflection film comprising a film body and an undercoat layer laminated on the optical component side of the film body, the optical film thickness of the undercoat layer being smaller than λ / 2.

[0007] The present invention is an optical component for laser light having a wavelength λ, and is provided with the antireflection film of the present invention so as to cover the light incident surface and / or the light exit surface. Effect of the Invention

[0008] According to the present invention, the optical film thickness of the undercoat layer laminated on the optical component side of the film body in the antireflection film is smaller than λ / 2, so that high resistance to laser light can be obtained. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an anti-reflection film according to an embodiment. [Diagram 2] 11 is a cross-sectional view of a modified example of the antireflection film according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments will be described in detail below.

[0011] 1 shows an anti-reflection film 10 according to an embodiment. The anti-reflection film 10 is provided so as to cover a light entrance surface and / or a light exit surface of an optical component 20 for laser light having a wavelength λ.

[0012] Here, examples of the optical component 20 on which the antireflection coating 10 according to the embodiment is provided include solid-state lasers, gas lasers, semiconductor lasers, optical fibers, optical fiber elements, various lenses, Faraday rotators, wavelength conversion elements, quartz blocks, quartz substrates, etc. Examples of the solid-state lasers include glass lasers and YAG lasers, etc. Examples of the gas lasers include CO2 lasers and excimer lasers, etc. The wavelength λ of the laser light used by the optical component 20 is, for example, 190 nm or more and 1100 nm or less.

[0013] The antireflection film 10 according to the embodiment includes a film body 11 and an undercoat layer 12 laminated on the film body 11 on the optical component 20 side.

[0014] The film body 11 has a two-layer structure including a high refractive index layer 111 laminated directly on the undercoat layer 12, and a low refractive index layer 112 laminated directly on the high refractive index layer 111. The film body 11 may have a four-layer structure in which the high refractive index layers 111 and the low refractive index layers 112 are alternately laminated as shown in Fig. 2, or may have a six-layer structure or an eight-layer structure.

[0015] Examples of materials for forming the high refractive index layer 111 include Ta2O5, Nb2O5, HfO2, Al2O3, and ZrO2. The thickness of the high refractive index layer 111 is, for example, 30 nm or more and 70 nm or less. Examples of materials for forming the low refractive index layer 112 include SiO2, etc. The thickness of the low refractive index layer 112 is, for example, 230 nm or more and 255 nm or less.

[0016] The undercoat layer 12 is provided so as to be sandwiched between the high refractive index layer 111 of the film body 11 and the optical component 20. Examples of materials for forming the undercoat layer 12 include SiO2 and the like. The material for forming the undercoat layer 12 is preferably the same as the material for forming the light incident surface and / or the light exit surface of the optical component 20 with which the undercoat layer 12 is in contact. The optical thickness of the undercoat layer 12 is half the wavelength λ of the laser light used by the optical component 20, that is, smaller than λ / 2. The optical thickness of the undercoat layer 12 is the product of the refractive index n and the physical thickness d of the undercoat layer 12.

[0017] According to the antireflection coating 10 of the embodiment, the optical film thickness of the undercoat layer 12 laminated on the optical component 20 side of the film body 11 in the antireflection coating 10 is smaller than λ / 2, thereby making it possible to obtain high resistance to laser light. From the viewpoint of obtaining such high resistance to laser light, the optical film thickness of the undercoat layer 12 is preferably 0.15λ or less, more preferably 0.10λ or less, and even more preferably 0.08λ or less, and from the same viewpoint, it is preferably 0.02λ or more, and more preferably 0.04λ or more. EXAMPLES

[0018] (Anti-reflective film) <Example 1> An anti-reflection coating was produced by sequentially depositing an undercoat layer made of SiO2 (refractive index n: 1.44944) with a physical thickness of 29.8 nm (optical thickness: 43.2 nm), a high refractive index layer made of Ta2O5 with a thickness of 39.5 nm, and a low refractive index layer made of SiO2 with a thickness of 248.5 nm, in that order, on a SiO2 substrate. This was designated Example 1.

[0019] <Examples 2 to 4> Antireflection films were prepared in the same manner as in Example 1 except that the physical film thickness (optical film thickness) of the undercoat layer was 52.2 nm (75.7 nm), 74.5 nm (108.0 nm), and 104.3 nm (151.2 nm), and were designated as Examples 2 to 4, respectively.

[0020] <Comparative Example 1> An antireflection film was prepared as Comparative Example 1 in the same manner as in Example 1, except that no undercoat layer was provided.

[0021] <Comparative Example 2> An antireflection film was prepared as Comparative Example 2 in the same manner as in Example 1, except that the physical film thickness (optical film thickness) of the undercoat layer was 372.6 nm (540.1 nm).

[0022] (Damage Threshold) For each of Examples 1 to 4 and Comparative Examples 1 and 2, the wavelength λ of the YAG laser was 1080 nm, the pulse width was 10 nm, and the spot size (1 / e 2 ): The damage threshold was determined by the 1-on-1 method using a pulsed laser beam with a width of 370 μm and a length of 420 μm. The results are shown in Table 1.

[0023] [Table 1] [Industrial Applicability]

[0024] The present invention is useful in the technical field of antireflection films and optical components provided with the same. [Explanation of symbols]

[0025] 10 Anti-reflection coating 11 Membrane body 111 High refractive index layer 112 Low refractive index layer 12 Undercoat layer 20 Optical Components

Claims

1. An anti-reflection film provided to cover a light incident surface and / or a light exit surface of an optical component for laser light having a wavelength λ, A film body and an undercoat layer laminated on the optical component side of the film body, The optical thickness of the undercoat layer is smaller than λ / 2.

2. The anti-reflection coating according to claim 1 , The material forming the undercoat layer is SiO ２ and anti-reflective coatings.

3. The anti-reflection coating according to claim 1 , An anti-reflection film, wherein the material forming the undercoat layer is the same as the material forming the portion of the light incident surface and / or the light exit surface of the optical component with which the undercoat layer is in contact.

4. An optical component for laser light having a wavelength λ, 4. An optical component having an antireflection film according to claim 1 provided so as to cover a light incident surface and / or a light exit surface.

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