, the "kick" from the laser is so strong that the spring doesn't just stretch; it deforms. This deformation creates new frequencies and signals. Mathematically, we describe this by expanding the material's polarization ( as a power series: cap P raised to the open paren 1 close paren power Reflection, refraction, absorption. cap P raised to the open paren 2 close paren power (Second Order):
Leo looked back at the book. The diagrams didn't look like static lines anymore; they looked like a timeline. Hit, wait, hit, wait, hit, signal. , the "kick" from the laser is so
In a real experiment (like 2D Electronic Spectroscopy or Transient Absorption), you control the delays between pulses ( they looked like a timeline. Hit