= Robin M. Hochstrasser
{c}
= R. M. Hochstrasser
{c}
{synonym}
<Robin M. Hochstrasser> was a physical chemist working on molecular spectroscopy and dynamics. A primary Optica conference record explicitly gives this full-name spelling in the same coupled-vibrator and infrared-echo collaboration whose papers also use the byline R. M. Hochstrasser.<Nonlinear Responses of Coupled Vibrators through Frequency Resolved and Heterodyned Femtosecond Infrared Echoes by M. C. Asplund and others>[Publisher author record.]{ref}
With <M. C. Asplund> and <Martin T. Zanni>, <Robin M. Hochstrasser> coauthored the2000 phase-controlled peptide experiment in <two-dimensional infrared spectroscopy>. It used <heterodyne detection> to recover phase and amplitude of <vibrational photon echoes>, rather than measuring only an unsigned signal intensity.<Two-dimensional infrared spectroscopy of peptides by phase-controlled femtosecond vibrational photon echoes by M. C. Asplund and others>[Author byline and Abstract.]{ref}
An original field-addition example explains why phase matters. Two contributions of amplitude1 add to total amplitude2 and intensity4 when in phase; opposite-sign contributions cancel to0. Knowing each separate intensity was1 would not determine the combined result. With a known reference field $L$ and weak signal field $E$,
$$
|L+E|^2-|L|^2=2\operatorname{Re}(L^*E)+|E|^2.
$$
For a sufficiently strong reference, the cross term makes the weak field measurable with sensitivity to its relative phase. Changing reference phase samples different field components.
The spectroscopy's scientific power comes from using those controlled relations to constrain molecular interactions. A measured <2D IR cross peak> still requires a response model before it establishes a particular coupling or structural assignment. Coherent detection adds information; it does not remove the need for physical interpretation.
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