An assembly for converting a microscope into a phase contrast or a multi-modal microscope, the microscope comprising a microscope objective and a specimen stage, wherein the microscope objective is constructed and arranged to collect coherent light from a coherent light source directed toward the specimen stage, the assembly comprising: a first optical Fourier element that Fourier transforms light from the coherent light source, wherein the Fourier transform occurs in a Fourier plane; characterized by: a cell in the Fourier plane arranged to receive light from the first optical Fourier element, wherein the cell comprises liquid crystal molecules having a phase transition temperature, and wherein at temperatures exceeding the phase transition temperature, light transmitting through the liquid crystal molecules obtains a different phase than light transmitting through the liquid crystal molecules at temperatures below the phase transition temperature; a second optical Fourier element arranged to receive light from the cell and inversely Fourier transform the received light to provide an image; an image sensor that detects the image and generates an electronic representation of the image; and an adaptor capable of coupling the first and second Fourier elements (160, 170), the cell, and the image sensor to the microscope such that the first Fourier element Fourier transforms light collected by the microscope objective. a first optical Fourier element that Fourier transforms light from the coherent light source, wherein the Fourier transform occurs in a Fourier plane; characterized by: a cell in the Fourier plane arranged to receive light from the first optical Fourier element, wherein the cell comprises liquid crystal molecules having a phase transition temperature, and wherein at temperatures exceeding the phase transition temperature, light transmitting through the liquid crystal molecules obtains a different phase than light transmitting through the liquid crystal molecules at temperatures below the phase transition temperature; a second optical Fourier element arranged to receive light from the cell and inversely Fourier transform the received light to provide an image; an image sensor that detects the image and generates an electronic representation of the image; and an adaptor capable of coupling the first and second Fourier elements (160, 170), the cell, and the image sensor to the microscope such that the first Fourier element Fourier transforms light collected by the microscope objective. a cell in the Fourier plane arranged to receive light from the first optical Fourier element, wherein the cell comprises liquid crystal molecules having a phase transition temperature, and wherein at temperatures exceeding the phase transition temperature, light transmitting through the liquid crystal molecules obtains a different phase than light transmitting through the liquid crystal molecules at temperatures below the phase transition temperature; a second optical Fourier element arranged to receive light from the cell and inversely Fourier transform the received light to provide an image; an image sensor that detects the image and generates an electronic representation of the image; and an adaptor capable of coupling the first and second Fourier elements (160, 170), the cell, and the image sensor to the microscope such that the first Fourier element Fourier transforms light collected by the microscope objective.