Laser waveform generator

• US 3,879,109 A
• Filed: 06/21/1973
• Issued: 04/22/1975
• Est. Priority Date: 06/21/1973
• Status: Expired due to Term

• Current Assignee: Carlton F. Thomas
• Original Assignee: Carlton F. Thomas
• Inventors: Thomas, Carlton F.
• Primary Examiner(s): Sikes, William L.
• Application Number:
  US05/371,882
• Time in Patent Office: 670 Days
• Field of Search: 350/160,161,172,169 331/94.5 356/112,113 250/199
• US Class Current: 359/629
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G02B 27/0938 Using specific optical elements
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: G02B 27/108 for sampling a portion of a beam or combining a small beam in a larger one, e.g. wherein the area ratio or power ratio of the divided beams significantly differs from unity, without spectral selectivity
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/0071 Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction
• CPC Class Codes: Y02E 30/10 Nuclear fusion reactors

Abstract

An apparatus for generating a beam of electromagnetic energy of selected waveform. This invention takes an electromagnetic energy beam of short time duration and divides it, using suitable beamsplitters, into a series of separate beams. These separate beams are then individually tailored and recombined to form a composite beam equal to the sum of the individual beams.

Claims

1. In combination with a source of electromagnetic energy which provides an incident beam along a beam axis, an electromagnetic energy pulse shaper comprising, first beamsplitting means having a surface disposed to intersect said beam axis at a first angle with respect thereto, a beam incident upon said surface of said first beamsplitting means along said axis being partially transmitted through said first beamsplitting means and partially reflected, first reflective means disposed in proximity to said surface of said first beamsplitting means in position to intersect beams reflected from said surface of said first beamsplitting means, said first reflective means being separated from said surface by a first distance, a beam incident upon said first reflective means being reflected back onto said surface of said first beamsplitting means to be partially transmitted through said first beamsplitting means and partially reflected, said partial transmission and partial reflection of said first beamsplitting means and said reflection of said first reflective means splitting said beam incident along said beam axis into at least a first split beam transmitted through said first beamsplitting means from said incident beam and a second split beam transmitted through said first beamsplitting means after having been at least once reflected at said surface of said first beamsplitting means and by said first reflective means, said first and second split beams being separated in time by an amount proportional to said first distance, second beamsplitting means having a surface disposed to lie in the path of beams transmitted through said first beamsplitting means at a second angle with respect to said beam axis, said first and second split beams being partially transmitted through and partically reflected from said surface of said second beamsplitting means, and second reflective means disposed in proximity to said second beamsplitting means in position to intercept beams transmitted therethrough, said second reflective means being separated from said second beamsplitting means by a second distance which is unequal to said first distance, a beam incident upon said second reflective means being reflected back onto said second beamsplitting means, the reflection between said second reflective means and said second beamsplitting means combining said first and second split beams transmitted through said second beamsplitting means into a composite beam in which said first and second split beams are separated in time by an amount proportional to the difference between said first and second distances.

2. A combination of claim 1 wherein said first beamsplitting means are arranged parallel to said first reflective means.

3. The combination of claim 2 wherein said second beamsplitting means are arranged parallel to said second reflective means.

4. The combination set forth in claim 3 wherein said first angle is greater than said second angle.

5. The combination set forth in claim 1 wherein said first angle is unequal to said second angle.

6. The combination set forth in claim 1 wherein said first beamsplitting means has a first reflectance-transmittance ratio which defines the ratio of the intensity of said first split beam to said beam incident along said beam axis, and wherein said second beamsplitting means has a second reflectance-transmittance ratio which is unequal to said first refLectance-transmittance ratio.

7. The combination of claim 6 wherein the reflectance/transmittance ratio of said first beamsplitting means is greater than the reflectance/transmittance ratio of said second beamsplitting means.

8. The combination set forth in claim 1 further comprising attenuating means disposed between said first and second beamsplitting means to intercept and attenuate the intensity of at least one of said first and second split beams, the attenuated intensity of one of said first and second split beams being greater than the attenuated intensity of the other.

9. The combination set forth in claim 1 further comprising third reflective means disposed between said first and second beamsplitting means to intercept and reflect that portion of one of said first and second split beams which is reflected from said surface of said second beamsplitting means.

10. The combination set forth in claim 9 wherein said third reflective means is disposed to intersect and reflect that portion of said first split beam which is reflected from said surface of said second beamsplitting means.