Method for superresolution in an optical memory

Claim 2

A light beam method for optically resolving information stored in a data storage medium as areas of differing reflectivity comprising the steps of: directing light from a laser operating below threshold upon a surface containing at Least two areas of differing reflectivity, the laser and the surface aligned to reflect the impinging light back into the laser; adjusting the pumping power to the laser that the sum of the generated light plus reflected light from a desired portion of only the higher reflectivity area raises the laser above threshold causing lasing; and detecting the laser output difference associated with the lasing and nonlasing modes as indicative of the areas detected and the information stored.

Claim 3

The method of claim 1 wherein the laser is a semiconductor laser.

Claim 4

The method of claim 1 wherein the laser is a GaAs laser.

Claim 5

The method of claim 1 wherein the laser has one cavity face with an absolute reflectance of less than 0.5.

Claim 6

The method of claim 1 wherein the laser and the detecting means are a single integrated device.

Claim 7

The method of claim 1 wherein the laser light is directed upon a surface having at least two areas of common reflectivity separated by an area of different reflectivity and spaced apart by a distance less than that resolvable by the laws of optical diffraction.

Claim 8

A light beam method for optically resolving information stored in a data storage medium as areas of differing reflectivity comprising the steps of: directing light from a laser capable of lasing at two frequencies which have a common energy level, the lower gain frequency lasing by virtue of the selective reflectivity of one of the laser cavity mirrors and through that mirror to the surface having areas of differing reflectivity, the laser and the surface aligned to reflect the impinging light back into the laser; adjusting the pumping level of the laser that the reflectivity from a desired portion of only the higher reflectivity area of the surface raises the higher gain lasing frequency to a lasing level, extinguishing the lower gain frequency; and detecting the lasing frequency as indicative of the areas detected and the information stored.

Claim 9

A light beam method for optically resolving information stored in a data storage medium as areas of differing reflectivity comprising the steps of: directing light from a laser capable of lasing at two frequencies which have a common energy level, the lower gain frequency lasing by virtue of the selective reflectivity of one of the laser cavity mirrors and through that mirror to the surface having areas of differing reflectivity, the laser and the surface aligned to reflect the impinging light back into the laser; adjusting the pumping level of the laser that the reflectivity from a desired portion of only the higher reflectivity area of the surface raises the higher gain lasing frequency to a lasing level, extinguishing the lower gain frequency; and detecting the lasing frequency as indicative of the areas detected and the information stored.

Claim 10

The method of claim 7 wherein the laser is chosen from either a He-Ne or a Hg gas laser.

Claim 11

The method of claim 7 wherein the reflectivity of the mirror has a higher reflectivity for the lower gain frequency than the higher gain frequency.

Claim 12

The method of claim 7 wherein detecting the lasing frequency comprises detecting the lower gain frequency.

Claim 13

The method of claim 7 including focusing the laser beam onto the surface having areas of differing reflectivity.

Claim 14

The method of claim 7 wherein the laser light is directed upon a surface having at least two areas of common reflectivity separated by an area of different reflectivity and spaced apart by a distance less than that resolvable by the laws of optical diffraction.