Specifications include, but are not limited to: 1. Closed-Cycle, Low-Vibration Optical Cryostat 1A. Must offer closed-cycle, continuous cooling of samples to <4 Kelvin. 1B. Must offer operation at any sample temperature from 4 – 320 Kelvin. 1C. Must cool down the cold plate from room temperature to base temperature in less than 5 hours. 1D. Must have sample temperature stability of <15 mK. 1E. Must have cooling power at the cold plate of >75 mW at 5 K. 1F. Must have sample vibrations at base temperature relative to optical table of <10 nm peak to peak. 1G. Must have 30 or more heat sunk electrical feedthroughs, including the wires for controlling XYZ positioners (see item 2). 1H. Must have 4 or more heat sunk RF feedthroughs for 0-5 GHz frequencies, including semi-rigid coax wires to connect to sample. 1I. Cryostat must mount on existing user-supplied standard imperial optical table, or come with a vendor supplied standard imperial optical table. 1J. Cryostat must reach vacuum of <10^-5 Torr at room temperature, with vendor-supplied integrated turbo pump. 1K. High NA optical access to sample from low temperature objective (see item 3). 1L. Must have in-vacuum shield integrated mount for heat-sinking high NA low temperature objective (see item 3) to cold plate. 2. 3 Axis Scanning or Stepping Stage(s) for Positioning Sample and Controller 2A. Must offer >3 mm X, Y, and Z range of motion of sample with respect to objective. 2B. The stages must provide X and Y positioning of the sample. 2C. The stage providing positioning along the optical axis of the objective (Z) for focusing can move either the sample or the objective. 2D. Must offer positioning in all three axes with sub-micrometer precision (open loop operation is acceptable). 2E. Must operate at temperatures from 3-350 Kelvin and in vacuum. 2F. Must come with compatible controller with computer interface.