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Abstract Laser-assisted manufacturing (LAM) is a technique that performs machining of materials using a laser heating process. During the process, temperatures can rise above over 2000 °C. As a result, it is crucial to explore the thermal behavior of materials under such high temperatures to understand the physics behind LAM and provide feedback for manufacturing optimization. Raman spectroscopy, which is widely used for structure characterization, can provide a novel way to measure temperature during LAM. In this review, we discuss the mechanism of Raman-based temperature probing, its calibration, and sources of uncertainty/error, and how to control them. We critically review the Raman-based temperature measurement considering the spatial resolution under near-field optical heating and surface structure-induced asymmetries. As another critical aspect of Raman-based temperature measurement, temporal resolution is also reviewed to cover various ways of realizing ultrafast thermal probing. We conclude with a detailed outlook on Raman-based temperature probing in LAM and issues that need special attention. 

Temperature dependent Raman intensity of 2D materials features very rich information about the material's electronic structure, optical properties, and nm-level interface spacing. To date, there still lacks rigorous consideration of the combined effects. This renders the Raman intensity information less valuable in material studies. In this work, the Raman intensity of four supported multilayered WS 2 samples are studied from 77 K to 757 K under 532 nm laser excitation. Resonance Raman scattering is observed, and we are able to evaluate the excitonic transition energy of B exciton and its broadening parameters. However, the resonance Raman effects cannot explain the Raman intensity variation in the high temperature range (room temperature to 757 K). The thermal expansion mismatch between WS 2 and Si substrate at high temperatures (room temperature to 757 K) make the optical interference effects very strong and enhances the Raman intensity significantly. This interference effect is studied in detail by rigorously calculating and considering the thermal expansion of samples, the interface spacing change, and the optical indices change with temperature. Considering all of the above factors, it is concluded that the temperature dependent Raman intensity of the WS 2 samples cannot be solely interpreted by its resonance behavior. The interface optical interference impacts the Raman intensity more significantly than the change of refractive indices with temperature. 

Abstract Under photon excitation, 2D materials experience cascading energy transfer from electrons to optical phonons (OPs) and acoustic phonons (APs). Despite few modeling works, it remains a long‐history open problem to distinguish the OP and AP temperatures, not to mention characterizing their energy coupling factor (G). Here, the temperatures of longitudinal/transverse optical (LO/TO) phonons, flexural optical (ZO) phonons, and APs are distinguished by constructing steady and nanosecond (ns) interphonon branch energy transport states and simultaneously probing them using nanosecond energy transport state‐resolved Raman spectroscopy. ΔT_{OP −AP}is measured to take more than 30% of the Raman‐probed temperature rise. A breakthrough is made on measuring the intrinsic in‐plane thermal conductivity of suspended nm MoS₂and MoSe₂by completely excluding the interphonon cascading energy transfer effect, rewriting the Raman‐based thermal conductivity measurement of 2D materials.G_OP↔APfor MoS₂, MoSe₂, and graphene paper (GP) are characterized. For MoS₂and MoSe₂,G_OP↔APis in the order of 10¹⁵and 10¹⁴W m⁻³K⁻¹andG_ZO↔APis much smaller thanG_LO/TO↔AP. Under ns laser excitation,G_OP↔APis significantly increased, probably due to the reduced phonon scattering time by the significantly increased hot carrier population. For GP,G_LO/TO↔APis 0.549 × 10¹⁶W m⁻³K⁻¹, agreeing well with the value of 0.41 × 10¹⁶W m⁻³K⁻¹by first‐principles modeling.