Multifrequency rotatable scanning prisms

Claim 1

A method of constructing a prism for deflecting electromagnetic radiation in both a first wavelength range about a wavelength lambda 1 and a second wavelength range about a wavelength lambda 2 by the same final deflection angle D comprising the steps of: positioning along an optical axis an output subprism made of an output material with an output index of refraction n o and having an output face and an output intermediate face separated by an output prism opening angle A o ; forming an input subprism from an input material having an input index of refraction n i and having an input face and an input intermediate face separated by an input prism opening angle A i , with input and output materials being related by the conditions that the value of n o at the wavelength lambda 1 , is equal to the value of n i at the wavelength lambda 1 , n o (lambda 2 )=n i (lambda 1 ), and that n i (lambda 2 <n o (lambda 2 )<n i (lambda 1 ) and said input and output prism opening angles are related by the condition that radiation in said second wavelength range approaches said output face at an incident angle of sin- 1 [sin(D)/n o (lambda 2 )]; and positioning said input intermediate face in close proximity and substantially parallel to said output intermediate face along said optical axis.

Claim 2

A method of constructing a prism for deflecting electromagnetic radiation in both a first wavelength range about a wavelength lambda 1 and a second wavelength range about a wavelength lambda 2 by the same final deflection angle D comprising the steps of: positioning along an optical axis an output subprism made of an output material with an output index of refraction n o and having an output face and an output intermediate face separated by an output prism opening angle A o ; forming an input subprism from an input material having an input index of refraction n i and having an input face and an input intermediate face separated by an input prism opening angle A i , with input and output materials being related by the conditions that the value of n o at the wavelength lambda 1 , is equal to the value of n i at the wavelength lambda 1 , n o (lambda 2 )=n i (lambda 1 ), and that n i (lambda 2 <n o (lambda 2 )<n i (lambda 1 ) and said input and output prism opening angles are related by the condition that radiation in said second wavelength range approaches said output face at an incident angle of sin- 1 [sin(D)/n o (lambda 2 )]; and positioning said input intermediate face in close proximity and substantially parallel to said output intermediate face along said optical axis.

Claim 3

A method of constructing a prism for deflecting electromagnetic radiation in both a first wavelength range about a wavelength lambda 1 and a second wavelength range about a wavelength lambda 2 by the same final deflection angle D comprising the steps of: positioning along an optical axis an output subprism made of an output material with an output index of refraction n o and having an output face and an output intermediate face separated by an output prism opening angle A o ; forming an input subprism from an input material having an input index of refraction n i and having an input face and an input intermediate face separated by an input prism opening angle A i , with input and output materials being related by the conditions that the value of n i at both wavelengths lambda 1 and lambda 2 is greater than the corresponding value of n o at both said wavelengths lambda 1 and lambda 2 and that sin{A i +sin- 1 [sin(A o -A i )/n i (lambda)]} is less than or equal to n o (lambda)/n i (lambda) for said first and second wavelength ranges, with said opening angles A o and A i being determined by the conditions: alpha.sub.i =tan.sup.-1 [sin alpha.sub.0 -n.sub.i (lambda.sub.1) sin gamma.sub.1)/(cos alpha.sub.0 -n.sub.i (lambda.sub.1) cos gamma.sub.1)] and alpha.sub.0 =tan.sup.-1 [sin alpha.sub.0 (lambda.sub.2) sin gamma.sub.2)/(cos alpha.sub.0 -n.sub.1 (lambda.sub.2) cos gamma.sub.2)], where gamma.sub.1 sin.sup.-1 [n.sub.0 (lambda.sub.1)/n.sub.i (lambda.sub.1)]sin [(alpha.sub.0 -sin.sup.-1 (sin "0"/n.sub.0 (lambda.sub.1)))] and gamma.sub.2 =sin.sup.-1 [n.sub.0 (lambda.sub.2) sin/n.sub.i (lambda.sub.2)] sin [(alpha 0 - sin -1 (sin "0"/n 0 (lambda 2 ))]; and positioning said input intermediate face in close proximity and substantially parallel to said output intermediate face along said optical axis.

Claim 4

A method of constructing a prism for deflecting electromagnetic radiation in both a first wavelength range about a wavelength lambda 1 and a second wavelength range about a wavelength lambda 2 by the same final deflection angle D comprising the steps of: positioning along an optical axis an output subprism made of an output material with an output index of refraction n o and having an output face and an output intermediate face separated by an output prism opening angle A o ; forming an input subprism from an input material having an input index of refraction n i and having an input face and an input intermediate face separated by an input prism opening angle A i , with input and output materials being related by the conditions that the value of n i at both wavelengths lambda 1 and lambda 2 is greater than the corresponding value of n o at both said wavelengths lambda 1 and lambda 2 and that sin{A i +sin- 1 [sin(A o -A i )/n i (lambda)]} is less than or equal to n o (lambda)/n i (lambda) for said first and second wavelength ranges, with said opening angles A o and A i being determined by the conditions: alpha.sub.i =tan.sup.-1 [sin alpha.sub.0 -n.sub.i (lambda.sub.1) sin gamma.sub.1)/(cos alpha.sub.0 -n.sub.i (lambda.sub.1) cos gamma.sub.1)] and alpha.sub.0 =tan.sup.-1 [sin alpha.sub.0 (lambda.sub.2) sin gamma.sub.2)/(cos alpha.sub.0 -n.sub.1 (lambda.sub.2) cos gamma.sub.2)], where gamma.sub.1 sin.sup.-1 [n.sub.0 (lambda.sub.1)/n.sub.i (lambda.sub.1)]sin [(alpha.sub.0 -sin.sup.-1 (sin "0"/n.sub.0 (lambda.sub.1)))] and gamma.sub.2 =sin.sup.-1 [n.sub.0 (lambda.sub.2) sin/n.sub.i (lambda.sub.2)] sin [(alpha 0 - sin -1 (sin "0"/n 0 (lambda 2 ))]; and positioning said input intermediate face in close proximity and substantially parallel to said output intermediate face along said optical axis.