Patent ID: 7489401

Claim:
A micro-object emission light detecting device for detecting with a semiconductor light detecting element emission light emitted in the form of fluorescence or phosphorescence from a micro-object irradiated with excitation light emitted from an excitation light source; wherein said semiconductor light detecting element and said excitation light source are disposed coaxially or on one side, said micro-object emission light detecting device comprising: a Q switch laser that generates a short pulse laser in response to the irradiation with the excitation light, elevates a peak light intensity instantaneously, and irradiates the micro-object with a beam of short pulse laser as the excitation light; and a converging microlens that is inserted partway along a light path of the excitation light to converge the excitation light and elevate a peak light intensity of the excitation light and that irradiates the micro-object with the excitation light having the peak light intensity elevated; whereby emission light is generated from the micro-object due to two-photon absorption and detected with the semiconductor light detecting element wherein said Q switch laser is a passive type comprising a gain medium and a saturable absorber, and wherein the gain medium of said Q switch laser is a semiconductor with quantum well structure and the saturable absorber of said Q switch laser is also a semiconductor with quantum well structure.