Dynamic optical filter having a spatial light modulator

An optical filter, comprising:

• a light dispersive element which receives an optical input signal having various wavelength channels of light, which provides a separated light signal having said wavelength channels spatially distributed by a predetermined amount;
• a prism element, which receives said separated light having an incidence angle, and which provides a first stabilized light signal;
• a pixellating device, which receives said first stabilized light, having a two dimensional array of pixels, each of said channels being incident on a plurality of said pixels, each of said pixels having a first reflection state and a second reflection state in response to a pixel control signal, and said pixellating device providing a reflected separated light signal indicative of light provided from said first reflection state to said prism element;
• said prism element providing a second stabilized light signal in response to said reflected separated light signal, said second stabilized light being substantially independent of changes in said incidence angle of said separated light;
• and
• a light combining element, which receives said second stabilized light signal, recombines said second stabilized light signal, and provides an optical filter output signal indicative of a spectrally filtered optical input signal based on a filter function.

An optical filter, comprising:

• a light dispersive element which receives an optical input signal having various wavelength channels of light, which provides a separated light signal having said wavelength channels spatially distributed by a predetermined amount;
• an optical lens, located a predetermined lens distance from said dispersive element and having a lens focal length, which receives said separated light, and which provides a focussed light signal;
• a pixellating device, which receives said focussed light, having a two dimensional array of pixels, each of said channels being incident on a plurality of said pixels, each of said pixels having a first reflection state and a second reflection state in response to a pixel control signal, and said pixellating device providing a reflected separated light signal indicative of light provided from said first reflection state to said prism element;
• a light combining element, which receives said reflected separated light signal, recombines said reflected separated light signal, and provides an optical filter output signal indicative of a spectrally filtered optical input signal based on a filter function;
• and
• said lens distance being different from said focal length so as to provide a substantially constant optical loss over a predetermined wavelength range.

An optical filter, comprising:

• a light dispersive element which receives an optical input signal having various wavelength channels of light, which provides a separated light signal having said wavelength channels spatially distributed by a predetermined amount;
• a pixellating device, which receives said separated light, having a two dimensional array of pixels, each of said channels being incident on a plurality of pixels, each of said pixels having a first reflection state and a second reflection state in response to a pixel control signal, and said pixellating device providing a reflected separated light signal indicative of light provided from said first reflection state;
• said light dispersive element dispersing the optical channels of the input light onto said pixelating device to substantially overlap the optical channels on said pixellating device;
• and
• a light combining element, which receives said reflected separated light, recombines said reflected separated light, and provides an optical filter output signal indicative of a spectrally filtered optical input signal based on a filter function.

An dynamically selectable optical filter, comprising:

• a light dispersive element which receives an optical input signal having various wavelength channels of light, which provides a separated light signal having said wavelength channels spatially distributed by a predetermined amount;
• a pixellating device, which receives said separated light, having a two dimensional array of pixels, each of said channels being incident on a plurality of pixels, each of said pixels having a first reflection state and a second reflection state in response to a pixel control signal, and said pixellating device providing a reflected separated light signal indicative of light provided from said first reflection state;
• a light combining element, which receives said reflected separated light, recombines said reflected separated light, and provides an optical filter output signal indicative of a spectrally filtered optical input signal based on a filter function;
• and
• wherein said pixellating device is oriented such that the optical path length for a given wavelength channel is substantially constant across the projected image on the pixellating device.