Multiple-stage optical Kerr gate system

• US 5,227,912 A
• Filed: 10/30/1991
• Issued: 07/13/1993
• Est. Priority Date: 10/30/1991
• Status: Expired due to Fees

• Current Assignee: Ping-Pei Ho, Robert R. Alfano
• Original Assignee: Ping-Pei Ho, Robert R. Alfano
• Inventors: Alfano, Robert R., Ho, Ping-Pei
• Primary Examiner(s): Lerner, Martin
• Application Number:
  US07/784,220
• Time in Patent Office: 622 Days
• Field of Search: 359/247, 359/258, 359/250, 359/259, 372/12, 372/17, 372/27, 372/25, 372/700
• US Class Current: 359/258
• CPC Class Codes: G02F 1/3511 Self-focusing or self-trapping of light; Light-induced birefringence; Induced optical Kerr-effect
• CPC Class Codes: G02F 1/3515 All-optical modulation, gating, switching, e.g. control of a light beam by another light beam G02F1/353, G02F1/37, G02F1/39 take precedence
• CPC Class Codes: G02F 2203/26 Pulse shaping; Apparatus or methods therefor
• CPC Class Codes: Y10S 372/70 Optical delay

Abstract

A multiple-stage optical Kerr gate system for gating a probe pulse of light. In a first embodiment, the system includes at least two optical Kerr gates, each Kerr gate including a polarizer, an optical Kerr cell actuable by a pump pulse, and an analyzer. In a second embodiment, at least one of the Kerr cells may be eliminated by arranging the respective sets of polarizers and analyzers so that they share a common Kerr cell. Gated pulses obtained using the present system typically have a signal to noise ratio that is at least 500 times better than that for gated pulses obtained using a single optical Kerr gate system. The system of the present invention may also include means for causing the pump pulse to arrive at the second Kerr cell (in the case of the first embodiment) or at a single Kerr cell a second time (in the case of the second embodiment) non-synchronously with the arrival of the probe pulse thereat. In this manner, gated pulses may be obtained that are much shorter in duration than pulses gated with a single optical Kerr gate system.

Claims

1. A multiple-stage optical Kerr gate system for gating a signal pulse of light travelling along a path comprising:

a) a first optical Kerr gate disposed along the path of the signal pulse of light, said first optical Kerr gate comprising

i) a first polarizer for linearly polarizing the signal pulse of light in a first direction.

ii) a first optically-actuable Kerr cell disposed after the first polarizer for elliptically polarizing the linearly-polarized signal pulse of light, and

iii) a first analyzer disposed after said first optically-actuable Kerr cell, said first analyzer being crossed relative to said first polarizer;

b) a second optical Kerr gate disposed along the path of the signal pulse of light after said first optical Kerr gate, said second optical Kerr gate comprising

i) a second polarizer for linearly polarizing the signal pulse of light in a second direction, said second polarizer having a polarization axis parallel to that of said first analyzer,

ii) a second optically-actuable Kerr cell disposed after said second polarizer for elliptically polarizing the linearly-polarized signal pulse of light, and

iii) a second analyzer disposed after said second optically-actuable Kerr cell, said second analyzer being crossed relative to said second polarizer; and

c) means for directing a pump pulse of light onto said first and said second optically actuable Kerr cells in such a manner as to open said first and said second optical Kerr gates for passage of the signal pulse of light therethrough.

3. The multiple-stage optical Kerr gate system as claimed in claim 1 further comprising means for causing the pump pulse of light and the signal pulse of light to arrive non-synchronously at said second optically-actuable Kerr cell.

4. The multiple-stage optical Kerr gate system of claim 3 and wherein the causing means comprises a pair of parallel glass wedges.

5. The multiple-stage optical Kerr gate system as claimed in claim 1 wherein said means for directing the pump pulse of light includes one or more optical delay units for causing the pump pulse of light and the signal pulse of light to arrive non-synchronously at said second optically actuable Kerr cell.

2. The multiple-stage optical Kerr gate as claimed in claim wherein said first optical Kerr gate and said second optical Kerr gate are arranged collinearly.

6. A multiple-stage optical Kerr gate system for gating a signal pulse of light comprising:

a) an optically-actuable Kerr cell for elliptically polarizing linearly-polarized light;

b) a first polarizer for linearly polarizing light in a first direction;

c) a first analyzer said first analyzer being crossed relative to said first polarizer;

d) a second polarizer for linearly polarizing light in a second direction, said second polarizer having a polarization axis parallel to that of said first analyzer;

e) a second analyzer, said second analyzer being crossed relative to said second polarizer;

f) means for directing the signal pulse of light to traverse a path through said first polarizer, said optically-actuable Kerr cell, said first analyzer, said second polarizer, said optically-actuable Kerr cell, and said second analyzer, in that order. so that said first polarizer, said optically-actuable Kerr cell, and said first analyzer effectively form a first optical Kerr gate and said second polarizer, said optically-actuable Kerr cell, and said second analyzer effectively form a second optical Kerr gate; and

g) means for directing a pump pulse of light onto said optically actuable Kerr cell at such times so as to open said first and said second optical Kerr gates for passage of the signal pulse of light therethrough.

7. The multiple-stage optical Kerr gate system as claimed in claim 6 wherein said means for directing the pump pulse of light includes means for causing the pump pulse of light and the signal pulse of light, upon their second arrival at said optically-actuable Kerr cell, to arrive non-synchronously.

8. The multiple-state optical Kerr gate system as claimed in claim 7 wherein said causing means comprises one or more optical delay units.

9. A multiple sate optical Kerr gate system for gating a signal pulse of light travelling along a path comprising:

a. a first optical Kerr ate disposed along the path of the signal pulse of light, said first optical Kerr gate comprising;

i. a first polarizer for linearly polarizing the signal pulse of light in a first direction,

ii. a first optically actuable Kerr cell disposed after the first polarizer for elliptically polarizing the linearly polarized signal pulse of light, and

iii. a fist analyzer disposed after said first optically actuable Kerr cell, said first analyzer being crossed relative to said first polarizer;

b. a second optical Kerr gate disposed along the path of the signal pulse of light after said first optical Kerr gate, said second optical Kerr gate comprising;

i. a second polarizer for linearly polarizing the signal pulse of light in a second direction, said second polarizer having a polarization axis parallel to that of said first analyzer,

ii. a second optically actuable Kerr cell disposed after said second polarizer for elliptically polarizing the linearly polarized signal pulse of light, and

iii. a second analyzer disposed after said second optically actuable Kerr cell, said second analyzer being crossed relative to said second polarizer;

c. means for directing a pump pulse of light onto said first and said second optically actuable Kerr cells in such a manner as to open said first and said second optical Kerr gates for passage of the signal pulse of light therethrough; and

d. a stack of glass slides disposed along the path of the pump pulse of light after said first optically actuable Kerr cell and before said second optically actuable Kerr cell for causing the pump pulse of light and the signal pulse of light to arrive non synchronously at said second optically actuable Kerr cell.