Optical phase conjugation 4Pi microscope

A method for imaging using a 4-Pi Microscope, comprising:

• focusing a first light beam at a spatial point on a sample;
• detecting the first light beam that has been transmitted through the sample;
• outputting, using a spatial light modulator (SLM), a second light beam that is an optical phase conjugate of the first light beam, wherein the first light beam and the second light beam are counter propagating and the second light beam retraces a path of the first light beam, thereby automatically aligning the 4-pi microscope;
• focusing the second light beam, or allowing the second light beam to focus, on the sample at the spatial point;
• using the first light beam and the second light beam to excite fluorescence from the sample at the spatial point;
• and
• using the fluorescence to image the sample.

A method for assembling a 4-Pi microscope, comprising:

• (a) positioning:
• (i) a first objective for focusing a first light beam on a sample at a spatial point;
• (ii) one or more Digital Optical Phase Conjugation (DOPC) devices, wherein the DOPC devices each include:
• (1) a sensor for detecting the first light beam that has been transmitted through the sample and inputted on the sensor;
• and
• (2) a spatial light modulator (SLM) for outputting, in response to the sensor detecting the first light beam, a second light beam that is an optical phase conjugate of the first light beam;
• and
• (iii) a second objective positioned to transmit the first light beam to the sensor and focus the second light beam on the sample at the spatial point, so that the first light beam and the second light beam are counter-propagating and both focused to the spatial point.