Integrated spectrometer design with application to multiphoton microscopy.

We present a prism-based spectrometer integrated into a multifocal, multiphoton microscope. The multifocal configuration facilitates interrogation of samples under different excitation conditions. Notably, the image plane of the microscope and the image plane of the spectrometer are coincident eliminating the need for an intermediate image plane containing an entrance slit. An EM-CCD detector provides sufficient gain for spectral interrogation of single-emitters. We employ this spectrometer to observe spectral shifts in the two-photon excitation fluorescence emission of single CdSe nanodots as a function of excitation polarization.