  We present a general analytical solution to the problem of electromagnetic
scattering at a one-dimensional arbitrarily accelerated space-time
engineered-modulation (ASTEM) interface in the subluminal regime. We show that
such an interface fundamentally produces chirping, whose profile can be
designed according to specifications. This work represents an important step in
the development of ASTEM crystals and holds significant potential for
applications in microwave and optical devices reliant on chirp-based
functionalities.
