The tricorder (in the generic, non-trademarked sense) is a vital companion for any colonist to the outer Solar System. But what does it detect, and how?
Passive imaging. Using superlens/hyperlens/perfect lens technologies, the tricorder starts by viewing radio, terahertz, IR, visible, UV, and X-ray light in great detail. It can readily surpass the diffraction limit by using material with negative refractive index, or otherwise. It can "see" through opaque objects by selecting rare ballistic photons, or reconstructing the image from scattered light.
Active imaging. The tricorder contains a powerful attosecond laser that can be tuned and aimed by solid-state control. It uses all its optical tricks to narrow the beam to a precise point on objects to survey. This is not merely a rangefinder! It vaporizes a very small number of molecules (if not splitting them to atoms) on the surface of a sample, and after a predetermined delay, brightly illuminates them with the same or another wavelength, allowing the absorption frequencies to be measured precisely. This confirms chemical analysis that began with the terahertz scans. Additionally, the bright but momentary pulses of light provide illumination that spreads through the remainder of the object, which can be used to inform passive imaging because the light viewed can be filtered according to the distance and therefore the local speed of light, giving insight into the refractive index of the material along the route. Chirality of absorbing molecules is also assessed, because the laser can generate circularly polarized light to do circular dichroism analysis. Combining the circularly polarized laser channels with a preset phase differential produces conventionally polarized light to detect strain by polarimetry
Phonon diagnostics. As tricorders inevitably tend to be used on spaceships, detecting phonons to do diagnostics for cracks and strain is important. Ideally the means should work through vacuum, so I will suppose for now that the attosecond laser pulses generate a measurable vibration, like a smart speaker spying on your heatbeat, and the high quality terahertz optics picks it up.
Radiation seems like a weak spot. Anyone who has seen a Betagen pore over a gel would say radioactive imaging systems lack a wow factor. What can we do with this to make this modality more relevant?
Magnetometer. A SQUID magnetometer with room temperature superconductor should provide very sensitive imaging of electromagnetic fields. This can be used for microscopy and conducting MRI (nuclear magnetic resonance) in microtesla fields. NMR provides another very powerful tool for chemical analysis, and MRI for imaging inside living organisms.
Search for sentient lifeforms. (I couldn't help myself) This one is more difficult since a science of mind does not exist at this time coordinate. If we suppose that consciousness works by creating a temporal paradox by accessing future events, then it creates a situation where there are multiple valid mathematical solutions for the universe, and the selection of one of these to be "real" causes the classical Heisenberg interpretation of the collapse of the state-vector in quantum mechanics. Accordingly, the tricorder beams many entangled circularly polarized photons at the sample material with poor focus. Since it is impossible for the tricorder or anything else to detect which one goes with which, it does not measure their polarization, and the other entangled photon will pass tests for quantum key distribution. However, if the photons "interact" with a "sentient being", their state is measured on some random basis, and the other photon will no longer be reliably circularly polarized.
I have surely only scratched the surface here. The majority of all scientific research for the first two decades of the 21st century was focused on development of more effective government surveillance, and the tricorder is, in many ways, the culmination of that work. What technologies would you expect to find, or refuse to believe, for a top-quality tricorder manufactured in the Bhasan Char Free Trade Area in 2060?
- The tricorder focuses on sensing objects at a distance.
- The tricorder focuses on functions that work through vacuum or a range of atmospheres.
- The tricorder is a handheld device and images less than a steradian at once.
- The tricorder works only by sensing the environment - it is not a communications device and is meant to work while not in communication with anyone.