  Circular Dichroism (CD) can distinguish the handedness of chiral molecules.
However, it is typically very weak due to vanishing absorption at low molecular
concentrations. Here, we suggest Thermal Circular Dichroism (TCD) for chiral
detection, leveraging the temperature difference in the chiral sample when
subjected to right and left-circularly polarized excitations. The TCD combines
the enantiospecificity of circular dichroism with the higher sensitivity of
thermal measurements, while introducing new opportunities in the thermal domain
that can be synergistically combined with optical approaches. We propose a
theoretical framework to understand the TCD of individual and arrays of
resonators covered by chiral molecules. To enhance the weak TCD of chiral
samples, we first use individual dielectric Mie resonators and identify
chirality transfer and self-heating as the underlying mechanisms giving rise to
the differential temperature. However, inherent limitations imposed by the
materials and geometries of such resonators make it challenging to surpass a
certain level in enhancements. To overcome this, we suggest nonlocal thermal
and electromagnetic interactions in arrays. We predict that a combination of
chirality transfer to Mie resonators, collective thermal effects, and optical
lattice resonance could, in principle, offer more than 4 orders of magnitude
enhancement in TCD. Our thermonanophotonic-based approach thus establishes key
concepts for ultrasensitive chiral detection.
