# Wave Optics in Spacetimes with Compact Gravitating Object

## TL;DR

This paper explores wave optics phenomena in various spherically symmetric spacetimes, revealing how interference and diffraction effects influence observed wave patterns and spectra near compact objects like black holes and wormholes.

## Contribution

It provides numerical solutions for wave patterns and power spectra in different spacetimes, highlighting the roles of photon spheres and absorbing boundaries in wave interference.

## Key findings

- Oscillations in power spectrum due to photon sphere interference
- Diffraction effects caused by absorbing boundary conditions
- Characteristic oscillation periods depend on spacetime geometry

## Abstract

We investigate the wave optics in spherically symmetric spacetimes: Schwarzschild black hole, spherical star with a perfect absorbing surface, and massless/massive Ellis wormholes. Assuming a point wave source, wave pattern and power spectrums for scattering waves are obtained by solving the scalar wave equation numerically. We found that the power spectrum at the observer in the forward direction shows oscillations with two characteristic periods determined by the interference effect associated with the photon sphere and the diffraction effect due to the absorbing boundary condition inside of the photon sphere.