Multiphoton-excitation observation apparatus

1. A multiphoton-excitation observation apparatus comprising:

a light-source unit;

an observation apparatus main unit for irradiating a specimen with laser light emitted from the light-source unit and observing fluorescence emitted from the specimen; and

a control apparatus,

wherein the light-source unit includes

a pulsed laser light source for emitting pulsed laser light; and

an incidence-adjusting unit for adjusting the beam diameter of the laser light emitted from the pulsed laser light source, and

wherein the control apparatus controls the incidence-adjusting unit according to the depth of an observation plane in the specimen.

2. A multiphoton-excitation observation apparatus according to claim 1 , wherein the control apparatus includes a memory unit for storing, in association with each other, observation plane depths in the specimen and operating levels of the incidence-adjusting unit; obtains an operating level corresponding to the depth of the observation plane from the memory unit; and controls the incidence-adjusting unit with the obtained operating level.

3. A multiphoton-excitation observation apparatus according to claim 1 , wherein the control apparatus adjusts the intensity of the laser light irradiating the specimen according to the depth of the observation plane in the specimen.

4. A multiphoton-excitation observation apparatus according to claim 3 , wherein the control apparatus includes a memory unit for storing, in association with each other, observation plane depths in the specimen and laser light intensities; obtains from the memory unit a laser light intensity corresponding to the depth of the observation plane; and controls the light-source unit to output the obtained laser light intensity.

5. A multiphoton-excitation observation apparatus according to claim 3 , wherein the control apparatus includes a memory unit for storing, in association with each other, observation plane depths in the specimen and numbers of irradiated pulses of laser light; obtains from the memory unit a number of irradiated pulses of laser light corresponding to the depth of the observation plane; and controls the light-source unit to output the obtained number of irradiated pulses.

6. A multiphoton-excitation observation apparatus according to claim 2 , further comprising an input unit for inputting contents to be stored in the memory unit.

7. A multiphoton-excitation observation apparatus according to claim 1 , further comprising:

a laser scanning unit for scanning the laser light emitted from the light-source unit;

an objective optical system for focusing the laser light scanned by the laser scanning unit in the specimen; and

a light-detecting device for detecting fluorescence emitted from the focal position of the laser light in the specimen,

wherein the light-detecting device includes

a detector for outputting a detection signal according to the incident fluorescence; and

a detector controller for adjusting a detection sensitivity of the fluorescence in the detector according to the depth of the observation plane in the specimen.

8. A multiphoton-excitation observation apparatus according to claim 7 , wherein the detection controller adjusts at least one of the sensitivity of photo-electric conversion and an integration time of the output signal in the detector.

9. A multiphoton-excitation observation apparatus according to claim 7 , wherein

the light-detecting device includes a pinhole, and

the detection controller adjusts an opening diameter of the pin-hole.