Switching laser beam apparatus with recombined beam for recording

Claim 1

Apparatus comprising: a laser means for providing a laser beam at a predetermined average power level; a write signal having two states, a write state indicating when writing should take place and a read state indicating when only reading should take place; a frequency source means responsive to the write signal for selectively providing one of two signals at different frequencies, one in response to the write state, one in response to the read state; an rf amplifier means responsive to said one of two signals from said frequency source means for amplifying said one of two signals; and an acoustic optical modulator means responsive to the amplified one of two signals placed in the path of said laser beam for diffracting said beam into a zero order beam directed along a read path and a first order beam directed along one of two first order paths depending on which one of said two signals from said frequency source means is selected by said write signal: a write first order path directed toward a reflector means for diverting the first order laser beam back into the read path, and a read-only first order path directed toward a beam stop; whereby a laser means operated at a single power level is diverted into a read power zero order directed along a read path and a first order beam, and the further wherein the first order beam is selectively diverted back into the read path in response to a write signal to form a combined write beam.