Beam shaping system using diffraction

• US 5,237,451 A
• Filed: 11/04/1992
• Issued: 08/17/1993
• Est. Priority Date: 11/17/1989
• Status: Expired due to Fees

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Saxe, Steven G.
• Primary Examiner(s): Lerner, Martin
• Application Number:
  US07/971,675
• Time in Patent Office: 286 Days
• Field of Search: 350/162.16, 350/162.2, 350/162.22, 350/420, 350/421, 350/452, 350/3.71, 350/3.72, 350/96.12, 369/110, 369/112, 359/15, 359/19, 359/565, 359/569, 359/571, 359/574
• US Class Current: 359/565
• CPC Class Codes: G02B 13/08 Anamorphotic objectives
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G02B 27/0911 Anamorphotic systems
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06
• CPC Class Codes: G02B 27/4244 in wavelength selecting devices spectrometry G01J
• CPC Class Codes: G02B 27/425 in illumination systems mask illumination systems in photolithographic systems G03F7/70158
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence

Abstract

A beam shaping system for an astigmatic light source utilizes two lenses, both having diffractive power. A first lens shapes the beam in a first dimension and a second lens shapes the beam in a second dimension perpendicular to the first.

Claims

1. A beam shaping system for a diode laser said system having an optic axis along which a light beam emitted by a diode laser travels, said system comprising:

a first lens means having diffractive power said first lens means intersecting said optic axis and being perpendicular thereto, said first lens means being for shaping said beam in a first dimension, said diffractive power of said first lens means being provided by a plurality of linear diffractive zones, said diffractive zones being separated by optical steps; and

a second lens means having diffractive power said second lens means intersecting said optic axis and being perpendicular thereto, said second lens means being for shaping said beam in a second dimension, said second dimension being perpendicular to said first dimension, said diffractive power of said second lens means being provided by a plurality of linear diffractive zones said diffractive zones being separated by optical steps.

2. The beam shaping system of claim 1 wherein said diffractive zones of said first lens means being perpendicular to said diffractive zones of said second lens means.

3. The beam shaping system of claim 2 wherein each optical step provides a change in optical path length for said beam equal to λ

, where λ

is a design wavelength for said system.

4. The beam shaping system of claim 2 wherein some of said optical steps of each lens provide a change in optical path length for said beam equal to Jλ

and some of said optical steps of each lens provide a change in optical path length equal to Kλ

, where λ

is a design wavelength for said system and J and K are unequal integers.

5. The beam shaping system of claim 2 wherein said zones have linear contours.

6. The beam shaping system of claim 5 wherein each optical step provides a change in optical path length of said beam equal to λ

, where λ

is a design wavelength for said system.

7. The beam shaping system of claim 5 wherein some of said optical steps of each lens provide a change in optical path length for said beam equal to Jλ

and some of said optical steps of each lens provide a change in optical path length equal to Kλ

, where λ

is a design wavelength for said system and J and K are unequal integers.

8. The beam shaping system of claim 2 wherein said zones have hyperbolic contours.

9. The beam shaping system of claim 8 wherein each optical step provides a change in optical path length for said beam equal to λ

, where λ

is a design wavelength for said system.

10. The beam shaping system of claim 8 wherein some of said optical steps of each lens provide a change in optical path length for said beam equal to Jλ

and some of said optical steps of each lens provide a change in optical path length equal to Kλ

, where λ

is a design wavelength for said system and J and K are unequal integers.

11. The beam shaping system of claim 2 wherein said zones have stepwise contours.