# A Method to Address the Impact of Incident Conditions on the Spectral Reconstruction of the Talbot Wavemeter

## TL;DR

This paper introduces a new method to improve the accuracy of Talbot wavemeters by addressing issues caused by alignment errors.

## Contribution

A novel method using a double-grating structure to enhance tolerance to angular misalignment in Talbot wavemeters is proposed.

## Key findings

- The impact of incident conditions on interference patterns was derived and verified through simulations.
- Adding a grating with different periodicity generates Moiré fringes, increasing tolerance for angular misalignment.
- A Talbot wavemeter with a spectral resolution of 9 nm at 360 nm was successfully constructed.

## Abstract

The Talbot wavemeter has attracted widespread attention from researchers in recent years due to its advantages of miniaturization and low cost. However, the impact of varying incident conditions caused by factors such as alignment has remained a challenge for spectral retrieval. This paper first derives the influence of different incident conditions on the interference pattern based on Fresnel diffraction and verifies the derivation through simulations. We propose a method to address the impact of incident conditions on the interference pattern. By adding a grating with a different periodicity in front of the detector, Moiré fringes are generated in the periodicity dimension, increasing the fringe period and thus enlarging the tolerance for angular misalignment. Finally, we constructed a Talbot wavemeter based on a double-grating structure, achieving a spectral resolution of 9 nm at 360 nm. This method provides a reference for the future development of a high-precision, high-resolution Talbot wavemeter.