Origin of fluence-threshold discrepancy for photo-induced switching

Identify the underlying cause or combination of factors responsible for the higher observed laser fluence threshold required to stabilize the long-lived photo-induced metastable phase in La2/3Ca1/3MnO3 under 1030 nm, 250 fs, 1 kHz excitation compared to previously reported thresholds at 800 nm.

Background

The authors observe a threshold fluence of approximately 34.9 mJ/cm2 to stabilize a long-lived metastable phase using 1030 nm, 250 fs, 1 kHz excitation, contrasting with earlier reports of 8–12 mJ/cm2 at 800 nm.

They speculate that differences in excitation wavelength, pulse duration, and pumping protocol may contribute, but explicitly state that they cannot isolate a single factor responsible for the discrepancy.

References

While we cannot pinpoint the source of this discrepancy to a single factor, it is possible that it arises from a combination of differences in photo-excitation wavelength, laser pulse duration, and laser pumping protocol (pulse-picked vs. quasi-continuous 1 kHz excitation within a 30-second window) which will be discussed in later sections.

— Excitations across the equilibrium and photoinduced `hidden' states of magnetoresistive manganites  (2604.00991 - Fan et al., 1 Apr 2026) in Section I: Evolution of electric transport in LCMO driven by ultrafast photo-excitation