Patent US4281894A successfully refreshed from Google Patents.
US4281894A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Very low absorption, low efficiency laser beamsampler
Assignee: Applied Biosystems Inc
•
Filing: 1980-01-21
•
Granted: 1981-08-04
•
Expires: 2000-01-21
Abstract
Abstract A very low absorption beamsampler for diffracting a very small fraction of a laser beam while specularly reflecting substantially all of the main beam with minimal absorption. The beamsampler comprises a plane mirror surface coated with a high-reflectivity multilayer dielectric coating, the topmost dielectric of which is grooved into a grating and coated with a transparent dielectric having a refractive index very similar, but not the same, as the grooved layer to form a weak phase grating for diffracting a weak first order sampling beam.
Inventors
- 👤 Jayanta K. Guha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:07
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/10; G02B27/108; G02B27/1086; G02B5/00; G02B5/18; G02B5/1861
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
135 words
A very low absorption, low efficiency, laser beamsampler comprising: a plane reflective surface; a plurality of dielectric pairs overlying said reflective surface, each of said pairs comprised of a first layer of dielectric material having a high refractive index and a second layer of dielectric material having a low refractive index, said first and second layers being deposited in one-quarter wavelength optical thicknesses; a shallow groove diffraction grating formed in the top surface of the top layer of the top dielectric pair; and a protective layer of a third dielectric material applied over said diffraction grating, said third material applied to an optical thickness of substantially one-half wavelength, said third material having an index of refraction similar to, but different than, that of the dielectric material of said top layer of said top dielectric pair.
Claim 2
Dependent Claim
135 words
A very low absorption, low efficiency, laser beamsampler comprising: a plane reflective surface; a plurality of dielectric pairs overlying said reflective surface, each of said pairs comprised of a first layer of dielectric material having a high refractive index and a second layer of dielectric material having a low refractive index, said first and second layers being deposited in one-quarter wavelength optical thicknesses; a shallow groove diffraction grating formed in the top surface of the top layer of the top dielectric pair; and a protective layer of a third dielectric material applied over said diffraction grating, said third material applied to an optical thickness of substantially one-half wavelength, said third material having an index of refraction similar to, but different than, that of the dielectric material of said top layer of said top dielectric pair.
Claim 3
Dependent Claim
17 words
The beamsampler claimed in claim 1 wherein the dielectric material in said first layer is Zinc Sulfide.
Claim 4
Dependent Claim
17 words
The beamsampler claimed in claim 1 wherein the dielectric material in said first layer is Zinc Selenide.
Claim 5
Dependent Claim
20 words
The beamsampler claimed in claims 1, 2 or 3 wherein the dielectric material in said second layer is Thorium Fluoride.
Claim 6
Dependent Claim
30 words
The beamsampler claimed in claim 2 wherein said grating is formed in the top surface of a top layer of Zinc Sulfide, and said third dielectric material is Zinc Selenide.
Claim 7
Dependent Claim
30 words
The beamsampler claimed in claim 3 wherein said grating is formed in the top surface of the top layer of Zinc Selenide and said third dielectric material is Zinc Sulfide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |