Figure 2. Emission spectra from the three sand lasers considered.
Spectra collected from right (red line) and left (black line) sand grains of device #1, (a) device #2, (b) and device #3, (c). The pump energy is EP = 53 pJ/μm2 in all experiments.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.