# Separated Schmidt modes in the angular spectrum of biphotons

## TL;DR

This paper demonstrates a method to prepare and measure high-dimensional quantum states (qudits) using the angular spectrum of biphotons, enabling efficient single-shot readout without filtering losses.

## Contribution

It introduces a technique to generate and detect Schmidt basis modes in biphoton angular spectra, improving quantum state manipulation and measurement efficiency.

## Key findings

- Modes are prepared in the Schmidt basis with non-overlapping intensity distributions.
- The method allows single-shot qudit readout without filtering losses.
- Enhanced control over high-dimensional quantum states in photonic systems.

## Abstract

We prepare qudits based on angular multimode biphoton states by modulating the pump angular spectrum. The modes are prepared in the Schmidt basis and their intensity distributions do not overlap in space. This allows one to get rid of filtering losses while addressing single modes and to realize a single-shot qudit readout.