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1.
J Am Coll Radiol ; 21(6S): S79-S99, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38823957

ABSTRACT

Asymptomatic adnexal masses are commonly encountered in daily radiology practice. Although the vast majority of these masses are benign, a small subset have a risk of malignancy, which require gynecologic oncology referral for best treatment outcomes. Ultrasound, using a combination of both transabdominal, transvaginal, and duplex Doppler technique can accurately characterize the majority of these lesions. MRI with and without contrast is a useful complementary modality that can help characterize indeterminate lesions and assess the risk of malignancy is those that are suspicious. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Subject(s)
Adnexal Diseases , Evidence-Based Medicine , Societies, Medical , Humans , Adnexal Diseases/diagnostic imaging , Female , United States , Diagnosis, Differential
2.
J Am Coll Radiol ; 21(6S): S3-S20, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38823952

ABSTRACT

This review focuses on the initial imaging in the reproductive age adult population with acute pelvic pain, including patients with positive and negative beta-human chorionic gonadotropin (ß-hCG) levels with suspected gynecological and nongynecological etiology. For all patients, a combination of transabdominal and transvaginal pelvic ultrasound with Doppler is usually appropriate as an initial imaging study. If nongynecological etiology in patients with negative ß-hCG is suspected, then CT of the abdomen and pelvis with or without contrast is also usually appropriate. In patients with positive ß-hCG and suspected nongynecological etiology, CT of the abdomen and pelvis with contrast and MRI of the abdomen and pelvis without contrast may be appropriate. In patients with negative ß-hCG and suspected gynecological etiology, CT of the abdomen and pelvis with contrast, MRI of pelvis without contrast, or MRI of pelvis with and without contrast may be appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Subject(s)
Pelvic Pain , Adult , Female , Humans , Pregnancy , Acute Pain/diagnostic imaging , Acute Pain/etiology , Evidence-Based Medicine , Pelvic Pain/diagnostic imaging , Societies, Medical , United States
4.
Opt Lett ; 48(21): 5531-5534, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37910695

ABSTRACT

We experimentally demonstrate how a concatenation of the standard and microstructure fiber segments permits adjusting the four-wave mixing sideband position over a large spectral range by varying the chirp of an input pulsed pump at a fixed wavelength in the presence of a self-phase modulation. The blue- and redshifted sidebands can stand aside over ∼200 nm and ∼450 nm from the pump, respectively, which agrees well with the numerical simulations. We validate our approach by showing the feasibility of CARS imaging.

5.
Opt Lett ; 48(17): 4582-4585, 2023 Sep 01.
Article in English | MEDLINE | ID: mdl-37656560

ABSTRACT

Hyperspectral spectroscopy requires light sources with wide spectral ranges from the visible to the mid-infrared. Here, we demonstrate the first fiber-based mid-infrared supercontinuum covering three octaves of frequency by leveraging 1-µm laser technology. The process consists in spectral broadening of a 1064-nm pump toward 0.48-2.5 µm in a graded-index multimode fiber, followed by a fluoro-indate fiber used to reach deeper into the near infrared (4.3 µm). Finally, an arsenic selenide chalcogenide fiber allows us to reach the 6-µm wavelength region, providing a 0.75-6-µm supercontinuum. We illustrate the potential of this light source by recording mid-infrared absorption spectra of organic compounds.

6.
Cureus ; 15(7): e42006, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37593305

ABSTRACT

A 34-year-old female smoker, with a history of pelvic endometriosis, presented with initial symptoms of shortness of breath and a choking sensation. She was found to have a right pneumothorax on chest x-ray. Over the next eight months, she ultimately underwent three tube thoracostomies, two video-assisted thoracoscopic surgeries (VATS), wedge resection, and repeated pleurodesis due to pneumothorax recurrence. She was seen multiple times post-surgically with the focus of treatment being smoking cessation rather than contraceptive therapy, despite an early follow-up visit noting that the initial symptoms coincided with her menstruation. The purpose of this article is to bring attention to this rarely diagnosed condition. With added awareness and understanding of the underlying causes and available treatments, medical providers could likely spare many women from similar experiences and dramatically improve the quality of their lives.

7.
Clin Imaging ; 101: 223-226, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37429168

ABSTRACT

PURPOSE: The COVID-19 pandemic rapidly accelerated the adoption of virtual learning in medical education, including departmental grand rounds lectures in radiology. This retrospective study sought to assess the impact of an open access virtual grand rounds program. We tested the hypothesis that virtual grand rounds would advance learning equity by increasing access to learners outside of our institution. METHODS: Twenty-two open access virtual grand rounds lectures were presented and recorded using an online videoconferencing platform. After the lecture, registrants received online access to the lecture recording for later on-demand viewing. The email address, geographical location, institutional affiliation, and medical specialty for all virtual registrants and attendees were retrospectively collected from a required online registration form. The primary outcome measure included an assessment of geographical diversity using descriptive statistics. RESULTS: Attendees of the virtual lectures were from 75 academic institutions and 27 non-academic institutions and located in 32 states, 88 cities, and 9 countries. Twenty-seven medical specialties were represented. CONCLUSION: The virtual grand rounds program in radiology contributes to free and open access educational content online for learners around the world. To address learning equity and promote international inclusion, we recommend that grand rounds organizers consider including a virtual option that allows free sharing of knowledge.


Subject(s)
COVID-19 , Radiology , Teaching Rounds , Humans , Retrospective Studies , Pandemics
8.
Radiographics ; 43(5): e220090, 2023 05.
Article in English | MEDLINE | ID: mdl-37079459

ABSTRACT

Placenta accreta spectrum (PAS) disorders are a major cause of maternal morbidity and mortality and are increasing in incidence owing to a rising rate of cesarean delivery. US is the primary imaging tool for evaluation of PAS disorders, which are most often diagnosed during routine early second-trimester US to assess fetal anatomy. MRI serves as a complementary modality, providing value when the diagnosis is equivocal at US and evaluating the extent and topography of myoinvasion for surgical planning in severe cases. While the definitive diagnosis is established by a combined clinical and histopathologic classification at delivery, accurate antenatal diagnosis and multidisciplinary management are critical to guide treatment and ensure optimal outcomes for these patients. Many MRI features of PAS disorders have been described in the literature. To standardize assessment at MRI, the Society of Abdominal Radiology (SAR) and European Society of Urogenital Radiology (ESUR) released a joint consensus statement to provide guidance for image acquisition, image interpretation, and reporting of PAS disorders. The authors review the role of imaging in diagnosis of PAS disorders, describe the SAR-ESUR consensus statement with a pictorial review of the seven major MRI features recommended for use in diagnosis of PAS disorders, and discuss management of these patients. Familiarity with the spectrum of MRI findings of PAS disorders will provide the radiologist with the tools needed to more accurately diagnose this disease and make a greater impact on the care of these patients. ©RSNA, 2023 Supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Jha and Lyell in this issue.


Subject(s)
Placenta Accreta , Radiology , Female , Humans , Pregnancy , Magnetic Resonance Imaging/methods , Placenta Accreta/diagnostic imaging , Placenta Accreta/epidemiology , Prenatal Diagnosis/methods , Radiography, Abdominal , Retrospective Studies
9.
Phys Rev Lett ; 130(6): 063801, 2023 Feb 10.
Article in English | MEDLINE | ID: mdl-36827573

ABSTRACT

Although the temperature of a thermodynamic system is usually believed to be a positive quantity, under particular conditions, negative-temperature equilibrium states are also possible. Negative-temperature equilibriums have been observed with spin systems, cold atoms in optical lattices, and two-dimensional quantum superfluids. Here we report the observation of Rayleigh-Jeans thermalization of light waves to negative-temperature equilibrium states. The optical wave relaxes to the equilibrium state through its propagation in a multimode optical fiber-i.e., in a conservative Hamiltonian system. The bounded energy spectrum of the optical fiber enables negative-temperature equilibriums with high energy levels (high-order fiber modes) more populated than low energy levels (low-order modes). Our experiments show that negative-temperature speckle beams are featured, in average, by a nonmonotonic radial intensity profile. The experimental results are in quantitative agreement with the Rayleigh-Jeans theory without free parameters. Bringing negative temperatures to the field of optics opens the door to the investigation of fundamental issues of negative-temperature states in a flexible experimental environment.

10.
Sci Rep ; 12(1): 21848, 2022 12 17.
Article in English | MEDLINE | ID: mdl-36528698

ABSTRACT

IOTA (International Ovarian Tumor Analysis) Simple Rules classifies adnexal masses as benign, malignant, or indeterminate based on sonographic features. We seek to determine if IOTA inappropriately directed women to surgery, or more aggressive surgery, than their final diagnosis warranted. This is a retrospective study of sonographically detected adnexal masses with known clinical outcomes from two institutions (n = 528). Surgically managed patients (n = 172) were categorized based on pathology and compared using Chi-square and t-test for categorical and continuous variables respectively. A logistic regression was used to predict characteristics that predicted surgery or imaging follow up of indeterminate masses. Of the 528 masses imaged, 29% (n = 155) underwent surgery for benign pathology. Only 1.9% (n = 10) underwent surgery after classification as malignant by IOTA for what was ultimately a benign mass. Surgical complications occurred in 10 cases (5.8%), all benign. Fifteen (3.2%) patients went into surgically induced menopause for benign masses, one of which was inaccurately classified by IOTA as malignant. Of the 41 IOTA indeterminate masses, the presence of soft tissue nodules on ultrasound was the only statistically significant predictor of the patient being triaged directly to surgery (OR 1.79, p = 0.04). Our findings support that the IOTA ultrasound classification system can provide clinical guidance without incurring unnecessary surgeries or surgical complications.


Subject(s)
Adnexal Diseases , Ovarian Neoplasms , Paraganglioma , Humans , Female , Retrospective Studies , Sensitivity and Specificity , Diagnosis, Differential , Adnexal Diseases/diagnostic imaging , Adnexal Diseases/surgery , Ultrasonography/methods , Ovarian Neoplasms/diagnostic imaging , Ovarian Neoplasms/surgery , Paraganglioma/diagnosis , Treatment Outcome
11.
J Am Coll Radiol ; 19(11S): S319-S328, 2022 11.
Article in English | MEDLINE | ID: mdl-36436959

ABSTRACT

Uterine fibroids (leiomyomas or myomas) are the most common neoplasm of the uterus. Though incompletely understood, fibroid etiology is multifactorial, a combination of genetic alterations and endocrine, autocrine, environmental, and other factors such as race, age, parity, and body mass index. Black women have greater than an 80% incidence of fibroids by age 50, whereas White women have an incidence approaching 70%. Fibroid symptoms are protean, and menorrhagia is most frequent. The societal economic burden of symptomatic fibroids is large, 5.9 to 34.3 billion dollars annually. There are a variety of treatment options for women with symptomatic fibroids ranging from medical therapy to hysterectomy. Myomectomy and uterine fibroid embolization are the most common uterine sparing therapies. Pelvic ultrasound (transabdominal and transvaginal) with Doppler and MRI with and without intravenous contrast are the best imaging modalities for the initial diagnosis of fibroids, the initial treatment of known fibroids, and for surveillance or posttreatment imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.


Subject(s)
Leiomyoma , Societies, Medical , Pregnancy , Humans , Female , Middle Aged , Evidence-Based Medicine , Leiomyoma/diagnostic imaging , Leiomyoma/therapy , Magnetic Resonance Imaging/methods , Ultrasonography, Doppler/methods
12.
Opt Express ; 30(10): 16104-16114, 2022 May 09.
Article in English | MEDLINE | ID: mdl-36221462

ABSTRACT

We demonstrate how spatial beam self-cleaning and supercontinuum generation in graded-index multimode optical fibers can be directly applied in multiplex coherent anti-Stokes Raman Scattering (M-CARS) spectroscopy. Although supercontinuum generation causes pump depletion mainly in the center of the beam, the partial recovery of the pump brightness due to self-cleaning may enable self-referenced M-CARS, with no additional delay lines to synchronize pump and Stokes waves. As a proof-of-principle, we report examples of imaging of single chemical compounds and polystyrene beads. The new scheme paves the way towards simpler M-CARS systems based on multimode fiber sources.

13.
J Plast Reconstr Aesthet Surg ; 75(5): 1625-1631, 2022 05.
Article in English | MEDLINE | ID: mdl-35063384

ABSTRACT

Local chest wall perforator flaps (CWPFs) are a volume replacement technique permitting breast-conserving surgery in patients who otherwise may require a mastectomy. These flaps are based on one or more perforating arteries arising from the lateral chest wall that travel through the soft tissue and into the sub-dermal plexus to perfuse the flap. Examples include the lateral intercostal and lateral thoracic artery perforators (LICAP and LTAP, respectively). Cross-sectional imaging of perforating vessels is not routinely performed, and vessels are mapped pre- and peri-operatively using a hand-held acoustic doppler device. As many breast cancer patients undergo pre-operative MRI scanning for oncological purposes, we investigated the role of MRI in mapping the vascular anatomy to aid with the surgical planning of CWPFs. We collated data retrospectively on a cohort of breast cancer patients who underwent breast MRI as part of routine pre-operative imaging. Axial 3D high-resolution dynamic contrast-enhanced MRI sequences with multiplanar reconstructions were analysed by a consultant radiologist. The presence and calibre of lateral chest wall perforator vessels were assessed. Fifty patients were suitable for inclusion. A consistent pattern of lateral chest wall vasculature was observed. Forty-eight patients (96%) demonstrated a bilateral lateral thoracic artery (LTA) descending inferiorly along the chest wall with two-thirds of these communicating with perforating intercostal vessels. True independent LICAP vessels were identified in six patients. From our observations, lateral CWPFs are dependent on an intricate intercommunication between intercostal vessels and the LTA which in turn supply perforators to the lateral chest wall donor site.


Subject(s)
Breast Neoplasms , Mammaplasty , Perforator Flap , Thoracic Wall , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/surgery , Female , Humans , Magnetic Resonance Imaging , Mammaplasty/methods , Mastectomy , Perforator Flap/blood supply , Retrospective Studies , Thoracic Wall/diagnostic imaging , Thoracic Wall/surgery
14.
Folia Morphol (Warsz) ; 81(2): 503-509, 2022.
Article in English | MEDLINE | ID: mdl-33899206

ABSTRACT

BACKGROUND: Intervertebral disc (IVD) degeneration plays a crucial role in the pathophysiology of low back pain. Several grading systems have been developed for both morphological and radiological assessment. The aim of this study was to assess the morphological and radiological characteristics of IVD degeneration and validate popular radiological Pfirrmann scale against morphological Thompson grading system. MATERIALS AND METHODS: Full spinal columns (vertebrae L1-S1 and IVD between them) were harvested from cadavers through an anterior dissection. Magnetic resonance imaging scans of all samples were conducted. Then, all vertebral columns were cut in the midsagittal plane and assessed morphologically. RESULTS: A total of 100 lumbar spine columns (446 IVDs) were included in the analysis of the degeneration grade. Morphologic Thompson scale graded the majority of discs as grade 2 and 3 (44.2% and 32.1%, respectively), followed by grade 4 (16.8%), grade 1 (5.8%) and grade 5 (1.1%). The radiologic Pfirrmann grading system classified 44.2% of discs as grade 2, 32.1% as grade 3, 16.8% as grade 4, 5.8% as grade 1, and 1.1% as grade 5. The analysis on the effect of age on degeneration revealed significant, although moderate, positive correlation with both scales. Analysis of the agreement between scales showed weighted Cohen's kappa equal to 0.61 (p < 0.001). Most of the disagreement occurred due to a 1 grade difference (91.5%), whereas only 8.5% due to a 2 grade difference. CONCLUSIONS: With the increase of the prevalence of IVD disease in the population, reliable grading systems of IVD degeneration are crucial for spine surgeons in their clinical assessment. While overall there is agreement between both grading systems, clinicians should remain careful when using Pfirrmann scale as the grades tend to deviate from the morphological assessment.


Subject(s)
Intervertebral Disc Degeneration , Intervertebral Disc Displacement , Intervertebral Disc , Cadaver , Humans , Intervertebral Disc/diagnostic imaging , Intervertebral Disc Degeneration/diagnostic imaging , Lumbar Vertebrae/diagnostic imaging , Magnetic Resonance Imaging/methods
15.
Cureus ; 13(10): e18875, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34804724

ABSTRACT

Stress cardiomyopathy can cause significant morbidity in the functional life of patients. The most common finding is apical ballooning of the left ventricle on cardiac catheterization. Some cases present with atypical imaging findings. This report presents a case of atypical stress cardiomyopathy with midventricular hypokinesis.

16.
Br J Surg ; 108(10): 1181-1188, 2021 10 23.
Article in English | MEDLINE | ID: mdl-34370833

ABSTRACT

INTRODUCTION: Over half of women with surgically managed breast cancer in the UK undergo breast-conserving treatment (BCT). While photographs are shown prior to reconstructive surgery or complex oncoplastic procedures, standard practice prior to breast conservation is to simply describe the likely aesthetic changes. Patients have expressed the desire for more personalized information about likely appearance after surgery. The hypothesis was that viewing a three-dimensional (3D) simulation improves patients' confidence in knowing their likely aesthetic outcome after surgery. METHODS: A randomized, controlled trial of 117 women planning unilateral BCT was undertaken. The randomization was three-way: standard of care (verbal description alone, control group), viewing two-dimensional (2D) photographs, or viewing a 3D simulation before surgery. The primary endpoint was the comparison between groups' median answer on a visual analogue scale (VAS) for the question administered before surgery: 'How confident are you that you know how your breasts are likely to look after treatment?' RESULTS: The median VAS in the control group was 5.2 (i.q.r. 2.6-7.8); 8.0 (i.q.r. 5.7-8.7) for 2D photography, and 8.9 (i.q.r. 8.2-9.5) for 3D simulation. There was a significant difference between groups (P < 0.010) with post-hoc pairwise comparisons demonstrating a statistically significant difference between 3D simulation and both standard care and viewing 2D photographs (P < 0.010 and P = 0.012, respectively). CONCLUSION: This RCT has demonstrated that women who viewed an individualized 3D simulation of likely aesthetic outcome for BCT were more confident going into surgery than those who received standard care or who were shown 2D photographs of other women. The impact on longer-term satisfaction with outcome remains to be determined.Registration number: NCT03250260 (http://www.clinicaltrials.gov).


Most women with breast cancer are able to have an operation to remove the cancer while preserving the breast ('lumpectomy'). Whilst cancer control is the most important goal, appearance after surgery has been shown to affect long-term quality of life and is considered when planning treatment. Currently, surgeons simply describe the likely changes in appearance and, for more complex procedures, photographs of other women are shown. Patients themselves have indicated they would like more information regarding the likely changes to their breast after treatment. The authors have developed a way to simulate appearance following lumpectomy and radiotherapy using three-dimensional (3D) photographs. The study invited women undergoing lumpectomy to be assigned at random to one of three groups receiving standard care (discussion), a two-dimensional photograph, or the 3D simulation before their operation. The authors have demonstrated that showing a woman her simulation prior to surgery improves confidence going into treatment.


Subject(s)
Computer Simulation , Esthetics , Imaging, Three-Dimensional , Mammaplasty/psychology , Mastectomy, Segmental/psychology , Patient Education as Topic/methods , Aged , Breast Neoplasms/psychology , Breast Neoplasms/surgery , Female , Humans , Middle Aged , Photography
17.
Opt Lett ; 46(15): 3717-3720, 2021 Aug 01.
Article in English | MEDLINE | ID: mdl-34329264

ABSTRACT

We present a new, to the best of our knowledge, spatial-spectral mapping technique permitting measurement of the beam intensity at the output of a graded-index multimode fiber (GIMF) with sub-nanometric spectral resolution. We apply this method to visualize the fine structure of the beam shape of a sideband generated at 1870 nm by geometric parametric instability (GPI) in a GIMF. After spatial-spectral characterization, we amplify the GPI sideband with a thulium-doped fiber amplifier to obtain a microjoule-scale picosecond pump whose spectrum is finally broadened in a segment of InF3 optical fiber to achieve a supercontinuum ranging from 1.7 up to 3.4 µm.

18.
Opt Lett ; 46(6): 1289-1292, 2021 Mar 15.
Article in English | MEDLINE | ID: mdl-33720169

ABSTRACT

Most of the saturable absorbers commonly used to perform mode locking in laser cavities affect the trigger conditions of laser oscillation, which requires manually forcing the laser start-up by various means such as polarization controllers. We present a procedure for designing a laser cavity driven by a nonlinear optical loop mirror, which allows the laser to operate optimally without interfering with the oscillation triggering conditions, thus opening up possibilities for integration of this type of laser.

19.
BJS Open ; 5(1)2021 01 08.
Article in English | MEDLINE | ID: mdl-33609391

ABSTRACT

BACKGROUND: Participation in research can be beneficial for patients and healthcare providers, but may prove demanding at patient, clinician and organizational levels. Patient representatives are supportive of online research to overcome these challenges. The aim of this pilot study was to develop an online recruitment platform and test its feasibility and acceptability while evaluating the accuracy of participant-reported data. METHODS: The online research platform was developed in a 1-day 'hackathon' with a digital design company. Women who underwent implant-based breast reconstruction in 2011-2016 were invited by letter containing the web address (URL) of the study site and their unique study number. Once online, participants learned about the study, consented, entered data on demographics, treatment received and patient-reported outcome measures (BREAST-Q™), and booked an appointment for a single hospital visit for three-dimensional surface imaging (3D-SI). Real-time process evaluation was performed. The primary endpoint was recruitment rate. RESULTS: The recruitment rate was 40 per cent. Of the 100 women, 50 logged on to the platform and 40 completed the process through to 3D-SI. The majority of discontinuations after logging on occurred between consenting and entering demographics (3 women, 6 per cent), and between completing the BREAST-Q and booking an appointment for 3D-SI using the online calendar (3 women, 6 per cent). All women completed the online BREAST-Q™ once started. Participants took a median of 23 minutes to complete the online process. Patient-reported clinical data were accurate in 12 of 13 domains compared with electronic records (95 per cent concordance). Process evaluation demonstrated acceptability. CONCLUSION: The results of this pilot demonstrate the online platform to be acceptable, feasible, and accurate for this population from a single institution. The low-burden design may enable participation from centres with less research support and participants from hard-to-reach groups or dispersed geographical locations, but with online access.


Subject(s)
Mammaplasty , Patient Reported Outcome Measures , Telemedicine , Adult , Aged , Feasibility Studies , Female , Humans , Middle Aged , Pilot Projects
20.
Opt Lett ; 46(1): 66-69, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33362017

ABSTRACT

Characterization of the complex spatiotemporal dynamics of optical beam propagation in nonlinear multimode fibers requires the development of advanced measurement methods, capable of capturing the real-time evolution of beam images. We present a new space-time mapping technique, permitting the direct detection, with picosecond temporal resolution, of the intensity from repetitive laser pulses over a grid of spatial samples from a magnified image of the output beam. By using this time-resolved mapping, we provide, to the best of our knowledge, the first unambiguous experimental observation of instantaneous intrapulse nonlinear coupling processes among the modes of a graded index fiber.

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