Polarization modulation laser scanning microscopy

A polarization modulation laser scanning microscope comprising:

• a laser light source for emitting laser light;
• a polarization state generation unit (PSG) receiving the emitted laser light to provide prepared laser light having a linear polarization state a polarization direction of which is modulated at a frequency f;
• a first lens for focussing the prepared laser light on a sample laying upon an image plane;
• a second lens for collecting focused laser light transmitted through said image plane, the collected laser light having linearly and circularly polarized components;
• a polarization state analyzer unit (PSA) for selectively isolating linearly and circularly polarized components of said collected laser light;
• a signal detection unit for converting intensity of said linearly and circularly polarized components of said collected light to an oscillating analog signal;
• a signal demodulation unit having outputs including at least one specific harmonic of the oscillating analog signal;
• further comprising additional external microscopy means, said additional external microscopy means having outputs;
• and
• a relay interface having means for toggling between said outputs from said signal demodulation unit and said outputs from said additional external microscopy means.