An Automated Laboratory Laser Heating Arrangement for Materials Synthesis at High Temperatures and High Pressures

TL;DR

This paper presents an automated laser heating system for high-pressure, high-temperature material synthesis, enabling uniform, efficient, and precise heating of microscopic samples with minimal operator intervention.

Contribution

The paper introduces a novel automated rastering laser heating arrangement with LabVIEW control, improving uniformity and efficiency in high-pressure, high-temperature experiments.

Findings

Auto-raster heating produces better diamond formation signatures.

System allows heating of both microscopic and bulk samples.

Significantly reduces scan time compared to manual methods.

Abstract

This paper describes the automation of a laser heating arrangement for synthesizing and studying materials at high pressures (up to ~ 1 Mbar) and high temperatures (up to ~ 5000 K). In this arrangement, a diamond anvil high-pressure cell (DAC) containing a microscopic sample of typical diameter ~50-100 micrometer, is mounted on a precision X-Y nanomotor stage that forms part of an IR laser heating optical assembly. Automation of this stage has been accomplished using a LabVIEW virtual instrument program to manipulate the X and Y stages using nanopositioning systems. This has a major feature of enabling a rastered heating of the sample over a user-defined circular area, without any operator intervention in addition to a virtual joystick to position the sample with respect to the laser spot. This auto-rastering feature has the advantage of offering uniform exposure of a circular area of the sample to the incident heating laser beam apart from drastic reduction in scan time compared to a manual scan. The diameter of the circle can be varied from a maximum of ~24 mm down to the focal spot size of the laser (~few micrometers), enabling thereby usage of the laser heating arrangement for heating microscopic samples under high-pressure in a DAC, as well as bulk samples at atmospheric pressure. Examples for both macro and micro scale automated laser-heating experiments have been presented. In particular, at the micro scale, auto-raster heated carbon samples at ~ 17 GPa and ~2000 K showed excellent signatures of diamond formation compared to manually raster heated samples, highlighting the unique advantage of auto-raster heating.