Laser diode uniform illuminator
A fluorescence imaging system including a light source, an optical system, camera and an excitation light filter, the optical system produces a non-uniform fluence excitation illumination beam for illuminating an object and promoting fluorescence emissions, the optical system is positioned between the light source and the object, the optical system modifies the non-uniform fluence illumination beam into a uniform fluence illumination beam and changes the divergence of the uniform fluence illumination beam, the camera has an array of pixels, the camera detects the fluorescence emissions and performs pixel intensity measurements for each of the pixels, the excitation light filter is positioned between the object and the camera and filters out the excitation illumination beam, such that the excitation illumination beam does not reach the camera.
1. A fluorescence imaging system comprising:
a light source configured to produce a non-uniform fluence excitation illumination beam having a non-uniform beam fluence, said excitation illumination beam illuminating an object and configured for promoting fluorescence emissions;
an optical system optically coupled with said light source and positioned between said light source and said object, said optical system configured to modify said non-uniform fluence illumination beam into a uniform fluence illumination beam having a uniform beam fluence, said optical system configured to change the divergence of said uniform fluence illumination beam;
a vibrating diffuser;
a camera having an array of pixels, said camera being configured for detecting said fluorescence emissions and for performing pixel intensity measurements for each of said pixels; and
an excitation light filter positioned between said object and said camera, said excitation light filter configured for filtering out said excitation illumination beam, such that said excitation illumination beam does not reach said camera;
wherein said optical system comprises an optical fiber configured to receive said non-uniform fluence illumination beam from said light source, said optical system being further configured to reimage an output of said optical fiber onto an intermediate image plane as said uniform fluence illumination beam;
wherein said vibrating diffuser is located at said intermediate image plane and configured to vibrate along two non-parallel axes for modifying said non-uniform fluence illumination beam into said uniform fluence illumination beam having said uniform beam fluence; and
wherein a frequency of vibrations and an amplitude of vibrations of said vibrating diffuser are controlled in each of said two non-parallel axes such that irregularities on a surface of said vibrating diffuser are compensated for, thereby smoothing said excitation illumination beam into said uniform fluence illumination beam and providing substantial improvements in beam fluence uniformity over a vibrating diffuser vibrated along one axis.
2. The fluorescence imaging system of claim 1 , wherein said frequency of vibrations of said vibrating diffuser exceeds a frame rate of an image detector for detecting a fluorescence image of said object illuminated by said imaging system.