Abstract: An apparatus includes a first substrate of a first material having a first bonding surface, and one or more fluidic channels open at a plane of the first bonding surface. The apparatus also includes a different second material disposed on the first substrate. The second material connects two different portions of the one or more fluidic channels. An outer surface of the second material is at the plane of the first bonding surface at positions between the two portions. The apparatus also includes a second substrate having a second bonding surface in contact with the first bonding surface, the second substrate configured to confine fluid flow within the one or more fluidic channels. In a Joule-Thompson cryocooler apparatus, the first material is a first thermally insulating material and the second material is a thermally conductive material and the second substrate is made of a second thermally insulating material.

Abstract: A microcooler includes a substrate with a first and second microchannel and an orifice disposed between, in fluid communication with both. A pair of electrodes is in a vicinity of the orifice. An electrical resistive heating material is in electrical communication with the electrodes and is in thermal contact with a fluid in the vicinity of the orifice. A system includes the microcooler and a voltage source to apply a voltage across the electrodes, which induces sufficient heating in the heating material to disassociate something clogging the orifice, without significant damage to the heating material. Some systems include a sensor configured to detect an effect of clogging at the orifice. A processor is configured to receive sensor output from the sensor, and if there is an effect of clogging, then cause the voltage to be applied across the electrodes.

Abstract: A method includes etching one or more fluidic channels into a first substrate made of a first material according to a first spatial pattern. The method also includes, after etching the fluidic channels, then separately etching a space in the first substrate according to a different second pattern that includes at least one connection between at least two different portions of the fluidic channels. The method still further includes depositing a different second material into the space. The method yet further includes bonding a different second substrate to the first substrate to enclose the fluidic channels to configure them to contain or pass one or more fluids. For fabricating a Joule-Thomson cooler, the first substrate is made of a first thermally insulating material; the second material is a thermally conducting material; and the second substrate is made of a second thermally insulating material.