OmegaScope - The AFM Optical Platform

HORIBA Scientific has introduced a new AFM optical platform called OmegaScope. This latest turn-key solution integrates optics and ultra-resolution multi-range research AFM.

The OmegaScope AFM is also a sophisticated research instrument that offers a way for scientists focused on photonics and spectroscopy. It comes in reflection configurations, offering direct top and side optical access.

The adaptability of the OmegaScope platform provides almostendless possibilities inthe correlation of AFM imaging modes and high spatial resolution spectroscopies (fluorescence, photoluminescence, and Raman).

Features

No Interference of AFM Registration Laser with Raman Excitation Laser

The 1300 nm AFM laser does not intervene with the most well-known visible, UV, and near-IR Raman excitation lasers (364 to 830 nm) and removes any parasitic effect on VIS light-sensitive biological and photovoltaic samples.

Direct (Below Objective) Pathway to Cantilever

The OmegaScope system includes the optical and AFM channels that are fully separated. This independence does not restrict the required wavelength of Raman laser and considerably streamlines the adjustment of the entire system in contrast to the systems in which the AFM laser emerges through the same high-aperture objective as the Raman excitation laser.

The user can simply re-focus the high-aperture objective without having to make further re-adjustment of the AFM laser-to-cantilever installation. In addition, the OmegaScope’s design ensures less sensitivity to any acoustic noise and vibrations and offers relatively more AFM stability.

Easy, Quickand Repeatable Cantilever Adjustment

Thanks to the fixed AFM laser design, the excitation laser to cantilever tip adjustment can be made quickly and easily like never before. Furthermore, once a new cantilever of the same type is installed, the same spot (repeatability within a few microns) on the users’ sample surface can be found easily and scanned without any additional searching steps.

Automated AFM Registration System Adjustment

The SmartSPM scanning probe microscopes are the heart of the reflection configuration of the OmegaScope system and are also the first SPM with the motorized/automated laser-cantilever-photodiode alignment developed from scratch for combining with HORIBA spectrometers.

Fast Scanning

Scanner resonant frequencies of >7 kHz in XY and >15 kHz in Z are the highest in the AFM sector at present

Scanning can be done much faster than before through the optimized scanner control algorithms

Vibration Stability, Acoustic Stabilityand Fast Scanner with High Resonant Frequencies

Low drift, rapid response time, and metrological traceability. The best in the industry flexure-based closed-loop scanner with 100 x 100 x 15-micron scan range enables measurements of massive regions and simultaneously offers the true molecular resolution imaging.

The scanner’s high mechanical rigidity and the entire AFM are integral to the excellent performance of the OmegaScope and prevent the need for active vibration protection.

Such special properties also enable users to realize unique and more complex scanning algorithms, like Top mode. In this mode, the probe is lifted above the surface of the sample between the scanning points.

In every scanning point, the probe is brought back to the surface. The scanning signal is quantified as soon as the tip oscillation amplitude approaches the set threshold. This makes it possible to prevent any lateral force interactions and, for instance, secure TERS probes, but at the same time helps maintain the scanning rate up to 1 Hz.

Ease of Sample Replacement

The design of the OmegaScope AFM platform enables users to alter the samples with the cantilever holder and AFM head in place. It actually enhances the experiment’s reliability and safeguards the system from potential operator errors while performing regular processes.

Top and Side Optical Access

Top and side optical access to the tip-sample region allows users to examine the complete abilities of correlated AFM and spectroscopic imaging using VIS, IR, and UV high NA planapochromat objectives (side objective: up to 0.7 NA; top objective: up to 0.7 NA), which allow confocal detection of optical signal from the surface of the sample in a broad spectral range and the least size of excitation laser spot region.

The correctly designed side optical channel of the OmegaScope system plays a highly crucial role in successful TEPL and TERS experimentation, since it offers a relatively more considerable Z component of the optical field and effectively triggers the Plasmon resonance in the tip-sample junction.

Top and Side Objective Scanners

To optimally align the Raman laser beam and the AFM tip, the flexure-guided closed-loop XYZ objective scanners can be installed in the bottom, side, and top channels. Furthermore, this solution offers long-term stability, alignment automation, and the highest possible resolution, in addition to a broader spectral range with a few optical components in the light input/output system, thus reducing the wastage of useful optical signal.

Built-in DFM Measuring Made with PLL

The Dynamic Force Microscopy (DFM) mode is available as the standard option of the OmegaScope system. For this mode, a frequency modulation (FM) detector is developed by using the phase-locked loop (PLL) circuit integrated into the AIST-NT’s controller.

Through DFM, users can reliably sustain the minimal tip-sample interactions (that is, operation in the field of attractive forces), which can seem highly significant for successful scanning near-field optical microscopy (SNOM) and TERS experiments.

STM, Conductive AFMand SNOM Options

Simultaneously withspectroscopy measurements, the OmegaScope platform can be fitted with the special module through which users can quantify local currents in STM or AFM in three linear ranges (1 nA, 100 nA, and 10 μA). Such ranges can be changed within the software, where the needed bandwidth for each of them can be chosen from 100 Hz to 7 kHz.

The conductive module noise level of 60 fA in the measuring range of up to 1 nA and 1300 nm AFM laser simply sets a new benchmark for conductivity measurements in the field of photovoltaics.

Apart from the excellent flexibility of the OmegaScope AFM platform, the SNOM option based on the tuning fork feedback design can be effortlessly incorporated. Beyond the typical SNOM experiments, users may also follow the classics of nano-optics, particularly apertureless SNOM, with a system for near-field fluorescence imaging using a metal tip lighted up with femtosecond laser pulses of proper polarization.