We report room temperature operation of a II-VI p-i-n quantum confined Stark effect modulator using a ZnSe-Zn0.8Cd0.2Se multiple quantum well structure within a ZdSe p-n junction. A n-type ZnSe layer was used as a novel contact to the p-type ZnSe. Results are given for photovoltage spectroscopy, absorption, and differential absorption as a function of the applied electric field.

The processes involved in the stimulated emission by photopumping in (Zn, Cd)Se-ZnSe multiple quantum wells have been investigated at 77 K for a series of diferent well widths. It has been shown by means of photoluminescence-excitation spectroscopy that the confined excitons in the well play an important role in determining the lasing mechanism. The optical gain just above the lasing threshold is attributed to the recombination of an exciton accompanied by emission of one LO phonon. Far above threshold, inelastic exciton-exciton scattering processes contribute significantly to the gain.

The paper deals with space-charge interactions in the ion population trapped in the Orbitrap[Formula: see text] mass analyzer where the ions perform multiple quasi-harmonic oscillations in the axial direction. The many-particle problem for interacting ions is mathematically complicated and its solution, even numerical, is obstructed by the required precision of one per million to be maintained on a large number [Formula: see text] of oscillation periods. We develop a perturbation method based on the Bogoliubov–Krylov–Mitropolsky theory and derive averaged Hamiltonian equations in perturbations, which describe the evolution of the ions’ oscillation amplitudes and phases in so-called “slow” time. This approach provides a semi-analytical comprehensive model of resonant and nonresonant space-charge effects and allows fast and accurate numerical computation. Practical mitigation strategies for most deteriorating space-charge effects like coalescence and frequency shifts are considered.

The rapidly increasing adoption of high-resolution accurate-mass methods in analytical laboratories has fueled demand for instruments that combine high performance and reliability with small size and greater ease-of-use. This paper presents the major design principles that are driving the evolution of the hybrid quadrupole-Orbitrap instrument architecture to enable a greater range of applications and users. These principles may be summarized as follows: better usage of physical space and better access for service by means of size reduction of pumping and ion optics; expanded use of technologies from electronics in ion-optical design; flexibility in performance via modularity of design of the hardware and software components; and, harmonization of interfaces with other instruments to facilitate sharing and transferability of analytical workflows. The design of a novel family of hybrid mass spectrometers is described in detail, and performance evaluation is carried out on a wide variety of samples for its three representatives: the Orbitrap Exploris 120, Orbitrap Exploris 240 and Orbitrap Exploris 480 mass spectrometers.The new instrument family is shown to offer compelling potential not only for high-end proteomics and biopharmaceutical applications, but also for screening, trace, targeted and clinical analysis by liquid chromatography/mass spectrometry methods.

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