A system for optical wireless power transmission from a transmitter to at least one power receiving apparatus, said system comprising: an optical resonator having end reflectors (9,10) and a gain medium, said gain medium comprising either (i) a semiconductor material, or (ii) a solid host doped with Neodymium ions, said solid host being in optical communication with a filter attenuating radiation for at least one frequency having a wave number in the range 8,300 cm -1 to 12,500 cm -1, and wherein said gain medium: (a) is positioned inside said optical resonator, (b) has a first bandgap energy, and (c) is thermally attached to a cooling system (34,35), such that said gain medium is configured to amplify light passing through it, and said resonator is configured to emit an optical beam of said light; a driver configured to supply power to said gain medium, and enabling control of the small signal gain of said gain medium; a beam steering apparatus configured to direct said optical beam in at least one of a plurality of directions; an optical-to-electrical power converter located in said at least one power receiving apparatus, configured to convert said optical beam into electrical power, said optical-to-electrical power converter having a second bandgap energy smaller than said first bandgap energy; a detector configured to provide a signal indicative of said optical beam impinging on said optical-to-electrical power converter; and a controller adapted to receive from said system an indication of a hazardous situation, and to control at least one of the status of said beam steering apparatus and said driver, said controller receiving a signal at least from said detector, wherein said controller is further configured to respond to said indication of a hazardous situation by at least one of: (i) causing said driver to change the small signal gain of the gain medium; (ii) changing the radiance of said optical beam; (iii) changing the power supplied by said driver; (iv) changing the scan speed of said beam steering apparatus; (v) changing the scan pose of said beam steering apparatus; and (vi) recording the scan pose which defines the location of said optical-to-electrical power converter. an optical resonator having end reflectors (9,10) and a gain medium, said gain medium comprising either (i) a semiconductor material, or (ii) a solid host doped with Neodymium ions, said solid host being in optical communication with a filter attenuating radiation for at least one frequency having a wave number in the range 8,300 cm -1 to 12,500 cm -1, and wherein said gain medium: (a) is positioned inside said optical resonator, (b) has a first bandgap energy, and (c) is thermally attached to a cooling system (34,35), such that said gain medium is configured to amplify light passing through it, and said resonator is configured to emit an optical beam of said light; wherein said gain medium: (a) is positioned inside said optical resonator, (b) has a first bandgap energy, and (c) is thermally attached to a cooling system (34,35), (a) is positioned inside said optical resonator, (b) has a first bandgap energy, and (c) is thermally attached to a cooling system (34,35), such that said gain medium is configured to amplify light passing through it, and said resonator is configured to emit an optical beam of said light; a driver configured to supply power to said gain medium, and enabling control of the small signal gain of said gain medium; a beam steering apparatus configured to direct said optical beam in at least one of a plurality of directions; an optical-to-electrical power converter located in said at least one power receiving apparatus, configured to convert said optical beam into electrical power, said optical-to-electrical power converter having a second bandgap energy smaller than said first bandgap energy; a detector configured to provide a signal indicative of said optical beam impinging on said optical-to-electrical power converter; and a controller adapted to receive from said system an indication of a hazardous situation, and to control at least one of the status of said beam steering apparatus and said driver, said controller receiving a signal at least from said detector, wherein said controller is further configured to respond to said indication of a hazardous situation by at least one of: (i) causing said driver to change the small signal gain of the gain medium; (ii) changing the radiance of said optical beam; (iii) changing the power supplied by said driver; (iv) changing the scan speed of said beam steering apparatus; (v) changing the scan pose of said beam steering apparatus; and (vi) recording the scan pose which defines the location of said optical-to-electrical power converter. (i) causing said driver to change the small signal gain of the gain medium; (ii) changing the radiance of said optical beam; (iii) changing the power supplied by said driver; (iv) changing the scan speed of said beam steering apparatus; (v) changing the scan pose of said beam steering apparatus; and (vi) recording the scan pose which defines the location of said optical-to-electrical power converter.