The health state of an individual is closely linked to the glycosylation patterns of his or her blood plasma proteins. However, obtaining this information requires cost- and time-efficient analytical methods. We put forward infrared spectroscopy, which allows label-free analysis of protein glycosylation but so far has only been applied to analysis of individual proteins. Although spectral information does not directly provide the molecular structure of the glycans, it is sensitive to changes therein and covers all types of glycosidic linkages. Combining single-step ion exchange chromatography with infrared spectroscopy, we developed a workflow that enables the separation and analysis of major protein classes in blood plasma. Our results demonstrate that infrared spectroscopy can identify different patterns and global levels of glycosylation of intact plasma proteins.

Single-cycle optical pulses with controllable carrier-envelope phase (CEP) form the basis to manipulate the nonlinear polarization of matter on a sub-femtosecond time scale. We report a highly stable source of 6.9-fs, single-cycle pulses at 2.2 µm, based on a directly diode-pumped Cr:ZnS oscillator with 22.9-MHz repetition rate. Excellent agreement with simulations provides a precise understanding of the underlying nonlinear pulse propagation.

Molecular fingerprinting via vibrational spectroscopy characterizes the chemical composition of molecularly complex media, which enables the classification of phenotypes associated with biological systems. However, the interplay between factors such as biological variability, measurement noise, chemical complexity, and cohort size makes it challenging to investigate their impact on how the classification performs. Considering these factors, we developed an in silico model that generates realistic but configurable molecular fingerprints.

A diode-pumped Cr:ZnS amplifier is showcased, delivering 2.2 W of 35-fs pulses with low noise and high stability. This amplifier holds promise for generating ultrashort infrared pulses, particularly for ultrasensitive vibrational spectroscopy.

This study extends electric-field waveform control of ultrashort light pulses from visible to mid-infrared, generating single-cycle infrared pulses with broad applications, including material manipulation and molecular fingerprinting in biological systems.