Patent ID: 7746752

Claim:
A method of (a) effecting at least one of recording information on and reproducing information from a holographic recording medium and (b) performing servo control of an information recording and/or reproducing apparatus, said method comprising: generating a light beam having a first wavelength for effecting the at least one of recording of information on and reproducing information from the holographic recording medium; passing the light beam having the first wavelength through a dichroic polarized beamsplitter, which polarizes the light beam; irradiating the holographic recording medium with the polarized light beam having the first wavelength; generating a light beam having a second wavelength, different from the first wavelength, for performing servo control; reflecting the light beam having the second wavelength off of the dichroic polarized beamsplitter; irradiating the holographic recording medium with the light beam having the second wavelength reflected off of the dichroic polarized beamsplitter; reflecting (i) a first return light beam from the holographic recording medium, the first return light beam having the first wavelength, and (ii) a second return light beam from the holographic recording medium, the second return light beam having the second wavelength; directing the reflected first return light beam and the second return light beam to pass through the dichroic polarized beamsplitter; reflecting the first and second return light beams, having passed through the dichroic polarized beamsplitter, by a critical angle prism; causing the first and second return light beams reflected by the critical angle prism to be incident on the same light receiving element; separating signals from the light receiving element, a first signal representing recording and/or reproducing information and a second signal provided for performing servo control of the recording and/or reproducing apparatus; and performing servo control of the recording and/or reproducing apparatus based on the second signal.