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Browse Prior Art Database

Picosecond Laser Pulse Generator

IP.com Disclosure Number: IPCOM000081068D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Carlson, DG: AUTHOR

Abstract

This is a system for generating picosecond optical pulses that does not require the use of a mode-locked laser. The system, as seen in Fig. 1, includes an electrooptic switch 2, placed between two crossed polarizers 4 and 6 and a mirror 8 located adjacent polarizer 6. All the elements are outside of and in line with the output beam of a laser 10 which may be cw or pulsed. The electrically induced axes of the electrooptical crystal 12 are at 45 degrees to the axes of the polarizers. Polarizer 4 is of the type that transmits light in both polarizations but separates them spatially. For example, polarizer 4 could be a glass-air prism that deflects one polarization through 90 degrees but transmits the other polarization unchanged.

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Picosecond Laser Pulse Generator

This is a system for generating picosecond optical pulses that does not require the use of a mode-locked laser. The system, as seen in Fig. 1, includes an electrooptic switch 2, placed between two crossed polarizers 4 and 6 and a mirror 8 located adjacent polarizer 6. All the elements are outside of and in line with the output beam of a laser 10 which may be cw or pulsed. The electrically induced axes of the electrooptical crystal 12 are at 45 degrees to the axes of the polarizers. Polarizer 4 is of the type that transmits light in both polarizations but separates them spatially. For example, polarizer 4 could be a glass-air prism that deflects one polarization through 90 degrees but transmits the other polarization unchanged.

In the operation of this system, a pulsed rampage-voltage source 14 is employed that can deliver a voltage that is several times the half-wave voltage of the electrooptical switch 2. For a half-wave voltage of 100 volts, a drive voltage of 2900 volts was chosen for source 14, wherein the latter had a risetime of 0.3 nsec. Without mirror 8 in the system (Fig. 2A), the output of polarizer 6 consists of multiple pulses 16 (Fig. 2C) of full width at half-maximum of 10.6 picoseconds. By using a mirror 8 in the system, two things are accomplished.

1) Only one of the multiple pulses 16 is selected by adjusting the length L between electroptical switch and mirror. The length L is adjusted so that the leading pulse i...