Browse Prior Art Database

Laser Structure

IP.com Disclosure Number: IPCOM000080226D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gunn, JB: AUTHOR

Abstract

A transparent sphere having an index of refraction of 2 has complete spherical symmetry and has the property of bringing light from infinity to a focus exactly on its rear surface. Also, light which is internally reflected from the rear surface of such a spherical element returns along the same path, forming a collimated beam returning to the point of origin at infinity. Such spheres have the ability to act as retroflectors. Thus, two such spheres, however situated, can act as an optical resonator, and so can form the basis of a gas laser structure.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 79% of the total text.

Page 1 of 1

Laser Structure

A transparent sphere having an index of refraction of 2 has complete spherical symmetry and has the property of bringing light from infinity to a focus exactly on its rear surface. Also, light which is internally reflected from the rear surface of such a spherical element returns along the same path, forming a collimated beam returning to the point of origin at infinity. Such spheres have the ability to act as retroflectors. Thus, two such spheres, however situated, can act as an optical resonator, and so can form the basis of a gas laser structure.

In practice, the two spheres would be sealed to the two ends of a gas laser discharge tube, for example by solder glass. Because of their retroreflective properties, no accurate alignment is needed in this step. All that is required is that the line joining the centers of the spheres should be wholly within the bore of the discharge tube, and should pass through at least some of the active (inverted) region of the discharge. The spheres themselves do not need to be of any exact size, but only to be spherical within about lambda/4. Such spheres are amongst the cheapest of all optical elements to produce. Because of this, and of the lack of need for accurate alignment, a laser of this structure should be very cheap to manufacture.

If the reflectivity of the spheres is inadequate, it is a simple matter to add reflecting coatings to their outside surfaces after sealing to the tube. The beams from such a la...