Four-wave mixing seeded by a rapid wavelength-sweeping FDML laser for nonlinear imaging at 900 nm and 1300 nm.

Four-wave mixing (FWM) enables the generation and amplification of light in spectral regions where suitable fiber gain media are unavailable. The 1300 nm and 900 nm regions are of especially high interest for time-encoded (TICO) stimulated Raman scattering microscopy and spectro-temporal laser imaging by diffracted excitation (SLIDE) two-photon microscopy. We present a new, to the best of our knowledge, FWM setup where we shift the power of a home-built fully fiber-based master oscillator power amplifier (MOPA) at 1064 nm to the 1300-nm region of a rapidly wavelength-sweeping Fourier domain mode-locked (FDML) laser in a photonic crystal fiber (PCF) creating pulses in the 900-nm region. The resulting 900-nm light can be wavelength swept over 54 nm and has up to 2.5 kW (0.2 µJ) peak power and a narrow instantaneous spectral linewidth of 70 pm. The arbitrary pulse patterns of the MOPA and the fast wavelength tuning of the FDML laser (419 kHz) allow it to rapidly tune the FWM light enabling new and faster TICO-Raman microscopy, SLIDE imaging, and other applications.

Does the COVID-19 personal protective equipment impair the surgeon's performance?

INTRODUCTION: Despite increasing vaccination rates, new viral variants of SARS-CoV-2 (severe acute respiratory syndrome coronavirus type 2) are advancing the COVID 19 (coronavirus disease 2019) pandemic and continue to challenge the entire world. Surgical care of SARS-CoV-2 positive patients requires special protective measures. We hypothesized that "COVID-19" personal protective equipment (PPE) during surgery of SARS-CoV-2 positive or potentially positive patients would negatively affect the surgeon and thus the surgical outcome. MATERIALS AND METHODS: Ten experienced trauma surgeons participated in the study. Each surgeon performed two simulated surgeries of a distal tibial fracture on a Sawbone® under standardized conditions either wearing regular PPE or special COVID-19 PPE. Baseline values at rest were acquired for heart rate, blood pressure, saturation of peripheral oxygen (SpO2), respiratory rate and capillary blood gas (CBG) analysis including capillary partial pressure of oxygen (pO2) and carbon dioxide (pCO2), followed by four different standardized tests of attentional performance (TAP). Subsequently, the surgeon performed the first surgery according to a randomly determined order, with regular or COVID-19 PPE conditions in an operation theatre. After each surgery vital signs were acquired and CBG and TAP were performed again. RESULTS: In our simulated surgical procedure heart rate, respiratory rate, systolic and diastolic blood pressure did not show relevant differences. Percutaneously measured SpO2 decreased with additional layers of PPE, while CBG parameters were not affected. TAP tests showed a significant impairment of attention if PPEs were compared to the baseline, but both PPEs had similar results and no meaningful differences could be measured. CONCLUSIONS: According to our results, for surgical procedures additional PPE required during COVID-19 pandemic does not relevant affect the surgeon's mental and physical performance. Surgeries under COVID-19 PPE conditions appear safe and do not increase patient risk. LEVEL OF EVIDENCE: Level I.

Comparison of Arthroscopic versus Open Placement of the Fibular Tunnel in Posterolateral Corner Reconstruction.

INTRODUCTION: Precise fibular tunnel placement in posterolateral corner (PLC) reconstruction is crucial in restoring rotational and lateral stability. Despite the recent progress of arthroscopic PLC reconstruction techniques, landmarks for arthroscopic fibular tunnel placement and a comparison to open tunnel placement have not yet been described. This study aimed to (1) identify reasonable soft-tissue and bony landmarks, which can be identified by either arthroscopy, fluoroscopy, or open surgery in anatomic fibular tunnel placement and (2) to compare accuracy and reliability of arthroscopic fibular tunnel placement with open surgery. MATERIALS AND METHODS: In a retrospective study, 41 magnetic resonance images (MRIs) of the knee were analyzed with emphasis on distances of an ideal anatomic fibular tunnel to 11 soft-tissue and bony landmarks. Subsequently, in eight cadaver knees, the ideal fibular tunnel was created arthroscopically and with a standard open technique from antero-latero-inferior to postero-medio-superior with a 2-mm K-wire. Positions of both tunnels were compared on postinterventional computed tomography scans. RESULTS: Based on MRI measurements, the anatomic tunnel entry should be 14.50 (±2.18) mm distal to the tip of the fibular styloid and 10.76 (±1.37) mm posterior to the anterior edge of the fibula. The anatomic fibular tunnel exit was located 12.89 (±2.35) mm below the tip of the fibular head. Arthroscopic fibular tunnel placement was reliable in all cases. Instead, in five out of the eight cases with open surgery, the fibular tunnel crossed the defined safety distance to the closest cortical edge/tibiofibular joint (distance < 8 mm). CONCLUSIONS: Reliable soft-tissue and bony landmarks of the fibular head allow arthroscopic anatomic fibular tunnel placement in PLC surgery, which shows a lower risk of tunnel malposition compared with open surgical techniques. Future studies will have to show whether clinical results of arthroscopic PLC reconstruction are in line with this study's technical results. LEVEL OF EVIDENCE: Level III.

Continuous spectral zooming for in vivo live 4D-OCT with MHz A-scan rates and long coherence.

We present continuous three-dimensional spectral zooming in live 4D-OCT using a home-built FDML based OCT system with 3.28 MHz A-scan rate. Improved coherence characteristics of the FDML laser allow for imaging ranges up to 10 cm. For the axial spectral zoom feature, we switch between high resolution and long imaging range by adjusting the sweep range of our laser. We present a new imaging setup allowing for synchronized adjustments of the imaging range and lateral field of view during live OCT imaging. For this, a novel inline recalibration algorithm was implemented that enables numerical k-linearization of the raw OCT fringes for every frame instead of every volume. This is realized by acquiring recalibration data within the dead time of the raster scan at the turning points of the fast axis scanner. We demonstrate in vivo OCT images of fingers and hands at different resolution modes and show real three-dimensional zooming during live 4D-OCT. A three-dimensional spectral zooming feature for live 4D-OCT is expected to be a useful tool for a wide range of biomedical, scientific and research applications, especially in OCT guided surgery.

Arthroscopic anatomy of the posterolateral corner of the knee: anatomic relations and arthroscopic approaches.

INTRODUCTION: Although open-surgical techniques for the reconstruction of the posterolateral corner (PLC) are well established, the use of arthroscopic procedures has recently increased. When compared with open surgical preparation, arthroscopic orientation in the PLC is challenging and anatomic relations may not be familiar. Nevertheless, a profound knowledge of anatomic key structures and possible structures at risk as well as technical variations of arthroscopic approaches are mandatory to allow a precise and safe surgical intervention. MATERIALS AND METHODS: In a cadaveric video demonstration, an anterolateral (AL), anteromedial (AM), posteromedial (PM) and posterolateral (PL) portal, as well as a transseptal approach (TSA) were developed. Key structures of the PLC were defined and sequentially exposed during posterolateral arthroscopy. Finally, anatomic relations of all key structures were demonstrated. RESULTS: All key structures of the PLC can be visualized during arthroscopy. Thereby, careful portal placement is crucial in order to allow an effective exposure. Two alternatives of the TSA were described, depending on the region of interest. The peroneal nerve can be visualized dorsal to the biceps femoris tendon (BT), lateral to the soleus muscle (SM) and about 3 cm distal to the fibular styloid (FS). The distal attachment of the fibular collateral ligament (FCL) can be exposed on the lateral side of the fibular head (FH). The fibular attachment of the popliteofibular ligament (PFL) is exposed at the tip of the FS. CONCLUSION: Arthroscopy of the posterolateral recessus allows full visualization of all key structures of the posterolateral corner, which provides the basis for anatomic and safe drill channel placement in PLC reconstruction. A sufficient exposure of relevant anatomic landmarks and precise portal preparation reduce the risk of iatrogenic vascular and peroneal nerve injury.

Lateral femoral notch sign and posterolateral tibial plateau fractures and their associated injuries in the setting of an anterior cruciate ligament rupture.

INTRODUCTION: ACL injury is one of the most common injuries of the knee joint in sports. As accompanying osseous injuries of the ACL rupture a femoral impression the so-called lateral femoral notch sign and a posterolateral fracture of the tibial plateau are described. However, frequency, concomitant ligament injuries and when and how to treat these combined injuries are not clear. There is still a lack of understanding with which ligamentous concomitant injuries besides the anterior cruciate ligament injury these bony injuries are associated. MATERIALS AND METHODS: One hundred fifteen MRI scans with proven anterior cruciate ligament rupture performed at our center were retrospectively evaluated for the presence of a meniscus, collateral ligament injury, a femoral impression, or a posterolateral impression fracture. Femoral impressions were described according to their local appearance and posterolateral tibial plateau fractures were described using the classification of Menzdorf et al. RESULTS: In 29 cases a significant impression in the lateral femoral condyle was detected. There was a significantly increased number of lateral meniscal (41.4% vs. 18.6% p = 0.023) and medial ligament (41.4% vs. 22.1%; p = 0.040) injuries in the group with a lateral femoral notch sign. 104 patients showed a posterolateral bone bruise or fracture of the tibial plateau. Seven of these required an intervention according to Menzdorf et al. In the group of anterior cruciate ligament injuries with posterolateral tibial plateau fracture significantly more lateral meniscus injuries were seen (p = 0.039). CONCLUSION: In the preoperative planning of ACL rupture accompanied with a positive femoral notch sign, attention should be paid to possible medial collateral ligament and lateral meniscus injuries. As these are more likely to occur together. A posterolateral impression fracture of the tibial plateau is associated with an increased likelihood of the presence of a lateral meniscal injury. This must be considered in surgical therapy and planning and may be the indication for necessary early surgical treatment.

Imaging Inflammation - From Whole Body Imaging to Cellular Resolution.

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.

Cavity length control for Fourier domain mode locked (FDML) lasers with µm precision.

In highly dispersion compensated Fourier domain mode locked (FDML) lasers, an ultra-low noise operation can only be achieved by extremely precise and stable matching of the filter tuning period and light circulation time in the cavity. We present a robust and high precision closed-loop control algorithm and an actively cavity length controlled FDML laser. The cavity length control achieves a stability of ∼0.18 mHz at a sweep repetition rate of ∼418 kHz which corresponds to a ratio of 4×10-10. Furthermore, we prove that the rapid change of the cavity length has no negative impact on the quality of optical coherence tomography using the FDML laser as light source.

Improved Visualization by Central Subluxation of the Lateral Meniscus in Comminuted Lateral Tibial Plateau Fractures.

The goal of surgical reconstruction of comminuted tibial plateau fractures is an anatomical reconstruction and stable fixation of the articular surface. This can be difficult due to poor visualization of the posterolateral and central segments of the articular surface of the proximal tibia. To improve visualization, the lateral approach can be extended with an osteotomy of the femoral epicondyle. In most cases, use of the extended lateral approach allows the whole lateral plateau to be visualized. Nevertheless, in some cases, an osteotomy alone is not enough to expose the entire fracture, especially the central segments of the tibial plateau. For these specific cases, we developed an additional technical trick that significantly improves articular visualization; the lateral meniscocapsular fibers are dissected allowing for central subluxation of the lateral meniscus, while leaving the anterior and posterior roots intact. With central subluxation of the lateral meniscus in comminuted tibial plateau fractures, the joint surface can be completely visualized, allowing an anatomical reduction even in highly complex fractures.

Flexible A-scan rate MHz-OCT: efficient computational downscaling by coherent averaging.

In order to realize adjustable A-scan rates of fast optical coherence tomography (OCT) systems, we investigate averaging of OCT image data acquired with a MHz-OCT system based on a Fourier Domain Mode Locked (FDML) laser. Increased system sensitivity and image quality can be achieved with the same system at the cost of lower imaging speed. Effectively, the A-scan rate can be reduced in software by a freely selectable factor. We demonstrate a detailed technical layout of the strategies necessary to achieve efficient coherent averaging. Since there are many new challenges specific to coherent averaging in swept source MHz-OCT, we analyze them point by point and describe the appropriate solutions. We prove that coherent averaging is possible at MHz OCT-speed without special interferometer designs or digital phase stabilization. We find, that in our system up to ∼100x coherent averaging is possible while achieving a sensitivity increase close to the ideal values. This corresponds to a speed reduction from 3.3 MHz to 33 kHz and a sensitivity gain of 20 dB. We show an imaging comparison between coherent and magnitude averaging of a human finger knuckle joint in vivo with 121 dB sensitivity for the coherent case. Further, the benefits of computational downscaling in low sensitivity MHz-OCT systems are analyzed.

Clinical results after surgical treatment of posterolateral tibial plateau fractures ("apple bite fracture") in combination with ACL injuries.

PURPOSE: The anterior cruciate ligament (ACL)-tear is a common injury in orthopaedic trauma. Depending on the energy of impact fractures of the posterolateral tibial plateau are often associated. Different morphologic variants of posterolateral tibial plateau impaction fractures have been described in the setting of an ACL-tear. Up to now an algorithm of treatment for a combined injury of a posterolateral tibial head fracture and an injury to the anterior cruciate ligament is missing. METHODS: We present a retrospective study with clinical and radiological analysis of posterolateral fractures in combination with ACL-tear. Impressions with a depth of more than 2 mm and/or a width that outreaches more than half of the posterior horn of the lateral meniscus with additional 3. degree positive pivot-shift-test indicated surgical treatment of the fracture with additional ACL repair or reconstruction. Clinical evaluation included follow-up examination, Visual Analog Scale (VAS), International Knee Documentation Committee Score (IKDC), functional and radiological Rasmussen score. RESULTS: 20 patients were included with a mean age of 43.6 ± 12.4 years. Mean follow-up was 18,2 ± 13,5 months. The fracture was arthroscopically reduced and percutaneously fixed with a screw osteosynthesis (Group 1), reduced via a dorsal approach without (Group 2) or with an autologous bone graft (Group 3). Subjective IKDC score was 79,15 ± 6,07. Functional Rasmussen scores ranged from 27 to 30 (mean 28 ± 2.71). Radiological Rasmussen scores ranged from 16 to 18 points (mean 16.75 ± 1.33). According to IKDC score (p = 0.60), functional Rasmussen score (p = 0.829) and radiological Rasmussen score (p = 0.679) no significant discrepancy between the groups were seen. There was no failure of the ACL graft recorded. CONCLUSIONS: Posterolateral tibial plateau fractures in combination with an ACL-tear, can cause persistent instability and increase rotational instability. Indication for treatment of these fractures is still under debate. From the biomechanical aspect the lack of more than 50% of the posterior horn of the lateral meniscus and dislocation/depression of more than 2 mm results in an increased rotational instability of the ACL deficient knee. Combined surgical treatment with ACL repair or reconstruction is a safe procedure that results in good, short-term clinical outcome, if our algorithm is followed. In addition this study shows, that majority of posterolateral tibial plateau fractures can be treated arthroscopically.

Extended approach to the lateral tibial plateau with central meniscal subluxation in fracture repair: feasibility and first clinical and radiographic results.

PURPOSE: Anatomic reduction in tibial plateau fractures remains to be demanding. For further visualisation of and approach to the joint surface an extended lateral approach using a lateral femoral epicondyle osteotomy and subluxation of the lateral meniscus was recently described. First clinical and radiographic mid-term results of this technique are presented in this feasibility study. METHOD: Ten complex tibial plateau fractures treated with extended lateral approach and lateral meniscal subluxation were prospectively analysed. Clinical and radiographic results were objectified according to the Rasmussen scores. RESULTS: After a median follow-up of 8.6 (IQR 4.3) months good to excellent clinical and radiographic results were noted. The clinical Rasmussen Score showed a median of 25 (IQR 2.8) and radiographic a median of 17 (IQR 2.0) points. CONCLUSION: Good to excellent clinical and radiological scores were obtained after using an extended lateral approach with lateral femoral epicondyle osteotomy and central meniscus subluxation. No approach specific complications could be observed.

Accuracy of navigated and conventional iliosacral screw placement in B- and C-type pelvic ring fractures.

INTRODUCTION: The objective of this study is to report the institutions experiences with standardized 2D computer-navigated percutaneous iliosacral screw placement (CNS), as well as the conventional fluoroscopically assisted screw placement method (CF) over a period of 10 years. PATIENTS AND METHODS: A total of 604 patients with sacral fractures (OTA B and C) were treated at the institution. Cases with both, a preoperative and postoperative CT scan were included for further analysis. With this prerequisite, a total of 136 cases were included. The quality of screw positioning, length of operation and intraoperative radiation exposure were recorded and compared. Moreover, it was analyzed whether the presence of dysmorphic sacra influenced the precision of screw positioning. RESULTS: Two hundred and thirty-two screws were implanted in 136 patients (100 navigated, 36 conventional). The duration of the average procedure was similar in the two groups [49.8 min (p = 0.7) conventional group (CF) vs. 48.0 min computer-navigated (CNS) group]. With computer navigation, radiation exposure was significantly reduced by almost half [128.3 vs. 65.2 s (p = 0.023)]. Screw placement was more accurate in the navigation group (79.03% CF vs. 86.47% CNS). The presence of dysmorphic sacral foramina or an increased alar slope increased the incidence of screw malpositioning. CONCLUSION: The conventional percutaneous method and a standardized 2D navigated method have similar rates of malpositioning. Dysmorphic upper sacral foramina and increased alar slope were identified as risk factors for screw malpositioning. Radiation exposure rates were reduced by half when using computer navigation. Therefore, computer navigation in iliosacral screw placement is recommended as method of choice.

An All-Arthroscopic Technique for Complex Posterolateral Corner Reconstruction.

Injuries to the posterolateral corner (PLC) often result in lateral, rotational, and dorsal instability, which need appropriate and differentiated treatment. Besides posterior cruciate ligament reconstruction for posterior instability, the technique according to LaPrade et al. efficiently stabilizes posterolateral rotational and lateral instability as described in Fanelli type B or C injuries. This technique has been exclusively used as an open procedure. In this article, we present an all-arthroscopic technique for the posterolateral stabilization procedure. To achieve this, 5 different arthroscopic portals are needed. The PLC is visualized by a trans-septal approach. Directly posterior to the popliteal tendon, arthroscopic preparation is started and the medial part of the fibular head is exposed. Two anatomic drill channels are placed in the lateral femoral condyle, with one tibial channel in the distal third of the sulcus popliteus and one channel in the fibular head. The popliteal tendon, popliteofibular ligament, and lateral collateral ligament are reconstructed with autologous hamstring tendons. The advantages of an all-arthroscopic anatomic PLC reconstruction are the protection of the soft tissues and the precise anatomic tunnel placement under direct visualization. The described procedure is a safe and anatomic method for posterolateral stabilization.

Correction: Live video rate volumetric OCT imaging of the retina with multi-MHz A-scan rates.

[This corrects the article DOI: 10.1371/journal.pone.0213144.].

Anatomic Reconstruction of the Posterolateral Corner: An All-Arthroscopic Technique.

Injuries of the posterolateral corner (PLC) of the knee lead to chronic lateral and external rotational instability. Successful treatment of PLC injuries requires an understanding of the complex anatomy and biomechanics of the PLC. Several open PLC reconstruction techniques have been published. It is understood that anatomic reconstruction is superior to extra-anatomic techniques, leading to better clinical results. An open, anatomic, fibula-based technique for reconstruction to address lateral and rotational instability has been described. However, when an open technique is used, surgeon and patient are faced with disadvantages, such as soft tissue damage or exposure of vulnerable structures. Few arthroscopic techniques for tibia- or fibula-based reconstruction of rotational posterolateral instability have been described. A complete arthroscopic stabilization of the combined lateral and posterolateral rotational instability of the knee has not yet been described. We therefore present the first all-arthroscopic technique for complete PLC reconstruction, based on an open technique described previously. All relevant landmarks of the PLC can be arthroscopically visualized in detail, allowing safe and effective treatment of PLC injuries.

Live video rate volumetric OCT imaging of the retina with multi-MHz A-scan rates.

Surgical microscopes are vital tools for ophthalmic surgeons. The recent development of an integrated OCT system for the first time allows to look at tissue features below the surface. Hence, these systems can drastically improve the quality and reduce the risk of surgical interventions. However, current commercial OCT-enhanced ophthalmic surgical microscopes provide only one additional cross sectional view to the standard microscope image and feature a low update rate. To present volumetric data at a high update rate, much faster OCT systems than the ones applied in today's surgical microscopes need to be developed. We demonstrate live volumetric retinal OCT imaging, which may provide a sufficiently large volume size (330x330x595 Voxel) and high update frequency (24.2 Hz) such that the surgeon may even purely rely on the OCT for certain surgical maneuvers. It represents a major technological step towards the possible application of OCT-only surgical microscopes in the future which would be much more compact thus enabling many additional minimal invasive applications. We show that multi-MHz A-scan rates are essential for such a device. Additionally, advanced phase-based OCT techniques require 3D OCT volumes to be detected with a stable optical phase. These techniques can provide additional functional information of the retina. Up to now, classical OCT was to slow for this, so our system can pave the way to holographic OCT with a traditional confocal flying spot approach. For the first time, we present point scanning volumetric OCT imaging of the posterior eye with up to 191.2 Hz volume rate. We show that this volume rate is high enough to enable a sufficiently stable optical phase to a level, where remaining phase errors can be corrected. Applying advanced post processing concepts for numerical refocusing or computational adaptive optics should be possible in future with such a system.

Prediction of Meniscal and Ligamentous Injuries in Lateral Tibial Plateau Fractures Based on Measurements of Lateral Plateau Widening on Multidetector Computed Tomography Scans.

BACKGROUND: The influence of increasing lateral plateau widening on the frequency of meniscal and ligamentous lesions in lateral tibial plateau fractures has been examined in very few studies using plain radiographs. Because the amount of this parameter cannot be measured accurately on plain radiographs, the purpose of this survey was to look for a possible correlation between the extent of lateral plateau widening, as measured on multidetector CT (MDCT) scans, and different soft-tissue injuries determined from magnetic resonance imaging (MRI). MATERIALS AND METHODS: 55 patients with a lateral tibial plateau fracture were included in this retrospective case series. Patient age averaged 52.6 years (SD = 18.0). The degree of lateral plateau widening was measured on CT images. MRIs were screened for meniscal and ligamentous injuries. RESULTS: We found a significant effect of increasing lateral plateau widening on the incidence of lateral meniscus lesions (P = 0.021), lateral collateral ligament tears (P = 0.047), and the overall quantity of meniscal and ligamentous lesions (P = 0.001). DISCUSSION: MRIs are not widely used as a diagnostic tool in lateral plateau fractures of the tibia. Reasons might be the costs and the fact that it is a time-consuming examination. The results of this study may help to estimate the probability of specific soft-tissue lesions in lateral tibial plateau fractures based on measurements of lateral plateau widening on MDCT scans, and they may guide the decision for additional MRI and/or arthroscopically assisted repair.

High-resolution retinal swept source optical coherence tomography with an ultra-wideband Fourier-domain mode-locked laser at MHz A-scan rates.

We present a new 1060 nm Fourier domain mode locked laser (FDML laser) with a record 143 nm sweep bandwidth at 2∙ 417 kHz  =  834 kHz and 120 nm at 1.67 MHz, respectively. We show that not only the bandwidth alone, but also the shape of the spectrum is critical for the resulting axial resolution, because of the specific wavelength-dependent absorption of the vitreous. The theoretical limit of our setup lies at 5.9 µm axial resolution. In vivo MHz-OCT imaging of human retina is performed and the image quality is compared to the previous results acquired with 70 nm sweep range, as well as to existing spectral domain OCT data with 2.1 µm axial resolution from literature. We identify benefits of the higher resolution, for example the improved visualization of small blood vessels in the retina besides several others.

Wavelength agile multi-photon microscopy with a fiber amplified diode laser.

Multi-photon microscopy is a powerful tool in biomolecular research. Less complex and more cost effective excitation light sources will make this technique accessible to a broader community. Semiconductor diode seeded fiber lasers have proven to be especially robust, low cost and easy to use. However, their wavelength tuning range is often limited, so only a limited number of fluorophores can be accessed. Therefore, different approaches have been proposed to extend the spectral coverage of these lasers. Recently, we showed that four-wave mixing (FWM) assisted stimulated Raman scattering (SRS) can be harnessed to red-shift high power pulses from 1064 nm to a narrowband output at 1122 nm and 1186 nm and therefore extend the number of accessible fluorophores. In this contribution, we show the applicability of all three wavelengths for multi-photon microscopy and analyze the performance.