Graphene-Enhanced Microbolometers for Terahertz Atmospheric Remote Sensing: A Comprehensive Physics-Based Model and Sensitivity Analysis

Terahertz (THz) frequencies are pivotal for atmospheric remote sensing of key species such as water vapor, ozone, and trace gases, yet traditional spaceborne THz detectors require cryogenic cooling, fundamentally limiting their deployment on resource-constrained CubeSat platforms. We present a comprehensive physics-based model of a graphene-enhanced microbolometer designed for near-room-temperature operation. The model uniquely integrates three critical components: 1) temperature-dependent thermal conductance with variable phonon scattering regimes, 2) Drude-Lorentz graphene conductivity including both intraband and interband transitions computed via the random-phase approximation, and 3) fundamental noise sources (phonon, Johnson, amplifier) with realistic physical parameters. We quantify the noise-equivalent power (NEP) as a function of critical design parameters: graphene Fermi level ($E_F$ ), thermal exponent ($n$ ), and bath temperature. The model achieves an NEP as low as $6.4\times {10}^{?12}\text{W}/\sqrt{\text{Hz}}$ at 1 THz in optimized regimes, with a balanced design space ($E_F\approx 0.4$ eV, $n\approx 3$ ) yielding $1.3\times {10}^{?11}\text{W}/\sqrt{\text{Hz}}$ . The gate-tunable absorption enables multi-spectral measurements without moving parts. Monte Carlo simulations of an atmospheric column retrieval show relative uncertainties around 0.5%, meeting typical science requirements. This framework provides a rigorous baseline for developing compact, low-power THz instruments for CubeSat constellations.