Işık Üniversitesi Kurumsal Akademik Belleği :: by Yazar "Karaman, Mustafa" değerine göre listeleniyor

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An Analog beamformer for integrated high-frequency medical ultrasound imaging
(IEEE, 2011) Gürün, Gökçe; Zahorian, Jaime; Tekeş, Coşkun; Karaman, Mustafa; Hasler, Paul E.; Değertekin, Fahrettin Levent
We designed and fabricated a dynamic receive beamforming integrated circuit (IC) in 0.35-mu m CMOS technology. This beamformer is suitable for integration with an ultrasound annular array for high-frequency (30-50 MHz) intravascular ultrasound (IVUS) imaging. The beamformer IC is capable of buffering, delaying and preamplification for 8 receive channels. We explored an analog delay cell based on a currentmode first-order all-pass filter, which is used as the basic building block to form an analog dynamic delay line. We also explored a bandwidth enhancement method on the delay cell that improved the overall bandwidth of the delay line by a factor of 6. Each delay cell consumes 2.1 mW of power and is capable of generating a tunable delay between 1.75 ns to 2.5 ns, enabling dynamic receive beamforming over a focal range from 1.4 mm to 2 mm. We successfully integrated the fabricated beamformer IC with an 8-element annular array. Our experimental test results demonstrated the desired buffering, preamplification and delaying capabilities of the beamformer.
An analog integrated circuit beamformer for high-frequency medical ultrasound imaging
(IEEE-INST Electrical Electronics Engineers Inc, 2012-10) Gürün, Gökçe; Zahorian, Jaime S.; Şişman, Alper; Karaman, Mustafa; Hasler, Paul E.; Değertekin, Fahrettin Levent
We designed and fabricated a dynamic receive beamformer integrated circuit (IC) in 0.35-mu m CMOS technology. This beamformer IC is suitable for integration with an annular array transducer for high-frequency (30-50 MHz) intravascular ultrasound (IVUS) imaging. The beamformer IC consists of receive preamplifiers, an analog dynamic delay-and-sum beamformer, and buffers for 8 receive channels. To form an analog dynamic delay line we designed an analog delay cell based on the current-mode first-order all-pass filter topology, as the basic building block. To increase the bandwidth of the delay cell, we explored an enhancement technique on the current mirrors. This technique improved the overall bandwidth of the delay line by a factor of 6. Each delay cell consumes 2.1-mW of power and is capable of generating a tunable time delay between 1.75 ns to 2.5 ns. We successfully integrated the fabricated beamformer IC with an 8-element annular array. Experimental test results demonstrated the desired buffering, preamplification and delaying capabilities of the beamformer.
An annular CMUT array beamforming system for high-frequency side looking IVUS imaging
(2010) Satır, Sarp; Gürün, Gökçe; Zahorian, Jaime S.; Karaman, Mustafa; Hasler, Paul E.; Değertekin, Fahrettin Levent
A CMUT annular array system for Side-Looking Intravascular Ultrasound (SL-IVUS) with fixed transmit and dynamic receive focusing capabilities has been developed. The system was experimentally characterized and validated through analytical models that simulate the beamformed transducer behavior. An 840 m diameter, 35MHz array was fabricated, characterized, and used in experiments. The array consists of curved 18m by 60m CMUT membranes that form 8 ring transducer elements with approximately equal areas. The beamforming system uses an IC chip consisting of 8 transimpedance amplifiers and delay elements for receive beamforming with adjustable delays between 2ns and 4ns, that are constant up to 50 MHz with close to unity gain. Transmit focusing is implemented with an FPGA controlled, high voltage pulser board that can generate adjustable electrical pulses with delays as small as 2ns. The system is characterized by measuring the radiation patterns of individual CMUT annular array elements as well as the unfocused and fixed transmit focused arrays. The results show predicted behavior including acoustic crosstalk effects at certain frequencies. For transmit-receive beamforming characterization, a 25m gold wire was imaged using 4 beamformed transmit elements and 4 beamformed receive elements with different delay values. The results show improved lateral resolution and lower side lobes with proper beamforming.
Annular CMUT arrays for side looking intravascular ultrasound imaging
(IEEE, 2007) Zahorian, Jaime; Güldiken, Rasim Oytun; Gürün, Gökçe; Qureshi, Muhammad Shakeel; Balantekin, Müjdat; Değertekin, Fahrettin Levent; Carlier, Stephane; Şişman, Alper; Karaman, Mustafa
Although side looking intravascular ultrasound (SL-IVUS) imaging systems using single element piezoelectric transducers set the resolution standard in the assessment of the extent of coronary artery disease, improvements in transducer performance are needed to perform harmonic imaging and high resolution imaging of vulnerable plaque. With their small channel count; annular arrays exploiting the inherent broad bandwidth of CMUTs and electronic focusing capability of integrated electronics provide a path for desired SL-IVUS imaging catheters. In this paper, we first describe the design, low temperature fabrication of an 8401 mu m diameter, 8 element CMUT annular array. Testing of the individual elements in oil shows a uniform device behavior with 100% fractional bandwidth around 20MHz without including the effects of attenuation and diffraction. We also present linear scan imaging results obtained on wire targets in oil, tissue and tissue mimicking phantoms using both unfocused and dynamically focused transducers. The results for axial and lateral resolution are in agreement predicted by the simulations and show the feasibility of this approach for high resolution SL-IVUS imaging.
Annular-ring CMUT arrays for forward-looking IVUS: Transducer characterization and imaging
(IEEE, 2006-02) Değertekin, Fahrettin Levent; Güldiken, Rasim Oytun; Karaman, Mustafa
In this study, a 64-element, 1.15-mm diameter annular-ring capacitive micromachined ultrasonic transducer (CMUT) array was characterized and used for forward-looking intravascular ultrasound (IVUS) imaging tests. The array was manufactured using low-temperature processes suitable for CMOS electronics integration oil a single chip. The measured radiation pattern of a 43 X 140- mu m(2) array element depicts a 40 degrees view angle for forward-looking imaging around a 15-MHz center frequency in agreement with theoretical models. Pulse-echo measurements show a -10-dB fractional bandwidth of 104% around 17 MHz for wire targets 2.5 mm away from the array in vegetable oil. For imaging and SNR measurements, RF A-scan data sets from various targets were collected using all interconnect scheme forming a 32-element array configuration. An experimental point spread function was obtained and compared with simulated and theoretical array responses, showing good agreement. Therefore, this study demonstrates that annular-ring CMUT arrays fabricated with CMOS-compatible processes are capable of forward-looking IVUS imaging, and the developed modeling tools can be used to design improved IVUS imaging arrays.
Beamforming and hardware design for a multichannel front-end integrated circuit for real-time 3D catheter-based ultrasonic imaging
(SPIE-Int Soc Optical Engineering, 2006) Wygant, Ira O.; Karaman, Mustafa; Oralkan, Ömer; Khuri-Yakub, Butrus Thomas
We are working on integrating front-end electronics with the ultrasound transducer array for real-time 3D ultrasound imaging systems. We achieve this integration by flip-chip bonding a two-dimensional transducer array to an integrated circuit (IC) that comprises the front-end electronics. The front-end IC includes preamplifiers, multiplexers, and pulsers. We recently demonstrated a catheter-based real-time ultrasound imaging system based on a 16 x 16-element capacitive micromachined ultrasonic transducer (CMUT) array. The CMUT array is flip-chip bonded to a front-end IC that includes a pulser and preamplifier for each element of the array. To simplify the back-end processing and signal routing on the IC for this initial implementation, only a single array element is active at a time (classic synthetic aperture (CSA) imaging). Compared with classic phased array imaging (CPA), where multiple elements are used on transmit and receive, CSA imaging has reduced signal-to-noise ratio and prominent grating lobes. In this work, we evaluate three array designs for the next generation front-end IC. The designs assume there are 16 receive channels and that numerous transmit pulsers are provided by the IC. The designs presented are: plus-transmit x-receive, boundary-transmit x-receive with no common elements, and full-transmit x-receive with no common elements. Each design is compared with CSA and CPA imaging. We choose to implement an IC for the full-transmit x-receive with no common elements (FT-XR-NC) design for our next-generation catheter-based imaging system.
CMUT-based volumetric ultrasonic imaging array design for forward looking ICE and IVUS applications
(SPIE-Int Soc Optical Engineering, 2013) Tekeş, Coşkun; Zahorian, Jaime S.; Xu, Toby; Rashid, Muhammad Wasequr; Satır, Sarp; Gürün, Gökçe; Karaman, Mustafa; Hasler, Jennifer Olson; Değertekin, Fahrettin Levent
Designing a mechanically flexible catheter based volumetric ultrasonic imaging device for intravascular and intracardiac imaging is challenging due to small transducer area and limited number of cables. With a few parallel channels, synthetic phased array processing is necessary to acquire data from a large number of transducer elements. This increases the data collection time and hence reduces frame rate and causes artifacts due to tissue-transducer motion. Some of these drawbacks can be resolved by different array designs offered by CMUT-on-CMOS approach. We recently implemented a 2.1-mm diameter single chip 10 MHz dual ring CMUT-on-CMOS array for forward looking ICE with 64-transmit and 56-receive elements along with associated electronics. These volumetric arrays have the small element size required by high operating frequencies and achieve sub mm resolution, but the system would be susceptible to motion artifacts. To enable real time imaging with high SNR, we designed novel arrays consisting of multiple defocused annular rings for transmit aperture and a single ring receive array. The annular transmit rings are utilized to act as a high power element by focusing to a virtual ring shaped line behind the aperture. In this case, image reconstruction is performed by only receive beamforming, reducing total required firing steps from 896 to 14 with a trade-off in image resolution. The SNR of system is improved more than 5 dB for the same frequency and frame rate as compared to the dual ring array, which can be utilized to achieve the same resolution by increasing the operating frequency.
Co-array optimization of CMUT arrays for forward-looking IVUS
(IEEE, 2009-09) Tekeş, Coşkun; Karaman, Mustafa; Değertekin, Fahrettin Levent
The ring annular array structure is a preferred configuration for implementing Forward-Looking IVUS (FLIVUS) catheters as it allows for volumetric imaging as well as use of a guidewire at the center. CMUT technology is promising for these arrays especially with the flexibility of locating array elements on the circular donut area efficiently. To take advantage of this flexibility, in this study, we introduce a new co-array sampling strategy that improves imaging performance while keeping the number of firings at a level suitable for real-time imaging. The presented co-array sampling strategy is based on the idea of adjusting the element density of the co-array rings in radial direction to suppress side lobes. In non-uniform sampling of the co-array with a given number of firings, the inter-element distances are adjusted both in radial and angular direction from inner ring to outer ring to fit a given apodization function. To test the imaging performance, we performed numerical simulations of the co-array with non-uniform sampling fitting to the raised-cosine apodization. The simulation results shows that sidelobe level can be reduced more than 10 dB by using non-uniform co-array sampling. This approach does use uniform weighting of all Tx and Rx elements in beamforming, and hence does not cause any SNR loss for apodization.
Coherent array imaging using phased subarrays. Part II: Simulations and experimental results
(IEEE-INST Electrical Electronics Engineers Inc, 2005-01) Johnson, Jeremy A.; Oralkan, Ömer; Ergün, Arif Sanlı; Demirci, Utkan; Karaman, Mustafa; Khuri-Yakub, Butrus Thomas
The basic principles and theory of phased subarray (PSA) imaging imaging provides the flexibility of reducing I he number of front-end hardware channels between that of classical synthetic aperture (CSA) imaging-which uses only one element per firing event-and full-phased array (FPA,) imaging-which uses all elements for each firing. The performance of PSA generally ranges between that obtained by CSA and FPA using the same array, and depends on the amount of hardware complexity reduction. For the work described in this paper, we performed FPA, CSA, and PSA imaging of a resolution phantom using both simulated and experimental data from a 3-MHz, 3.2-cm, 128-element capacitive micromachined ultrasound transducer (CMUT) array. The simulated system point responses in the spatial and frequency domains are presented as a means of studying the effects of signal bandwidth, reconstruction filter size, and subsampling rate on the PSA system performance. The PSA and FPA sector-scanned images were reconstructed using the wideband experimental data with 80% fractional bandwidth, with seven 32-element subarrays used for PSA imaging. The measurements on the experimental sector images indicate that, at the transmit focal zone, the PSA method provides a 10% improvement in the 6-dB lateral resolution, and the axial point resolution of PSA imaging is identical to that of FPA imaging. The signal-to-noise ratio (SNR) of PSA image was 58.3 dB, 4.9 dB below that of the FPA image, and the contrast-to-noise ratio (CNR) is reduced by 10%. The simulated and experimental test results presented in this paper validate theoretical expectations and illustrate the flexibility of PSA imaging as a way to exchange SNR and frame rate for simplified front-end hardware.
Coherent-array imaging using phased subarrays. Part I: Basic principles
(IEEE-INST Electrical Electronics Engineers Inc, 2005-01) Johnson, Jeremy A.; Karaman, Mustafa; Khuri-Yakub, Butrus Thomas
The front-end hardware complexity of a coherent array imaging system scales with the number of active array elements that are simultaneously used for transmission or reception of signals. Different imaging methods use different numbers of active channels and data collection strategies. Conventional full phased array (EPA) imaging produces the best image quality using all elements for both transmission and reception, and it has high front-end hardware complexity. In contrast, classical synthetic aperture (CSA) imaging only transmits on and receives from a single element at a time, minimizing the hardware complexity but achieving poor image quality. We propose a new coherent array imaging method-phased subarray (PSA) imagine-that performs partial transmit and receive beam-forming using a subset of adjacent elements at each firing step. This method reduces the number of active channels to the number of subarray elements; these channels are multiplexed across the full array and a reduced number of beams are acquired from each subarray. The low-resolution subarray images are laterally upsampled, interpolated, weighted, and coherently summed to form the final high-resolution PSA image. The PSA imaging reduces the complexity of the front-end hardware while achieving image quality approaching that of FPA imaging.
Çok katmanlı düzlemsel ortam için termoakustik dalga denkleminin çözümü
(IEEE, 2017-06-27) Bayıntır, Hazel; Ünalmış Uzun, Banu; İdemen, Mehmet Mithat; Karaman, Mustafa
Bu çalışmada, farklı akustik parametrelere sahip çok katmanlı düzlemsel ortam için tüm katmanlarda kaynak dağılımı olduğu varsayımı altında termoakustik dalga denkleminin analitik olarak düz ve ters çözümü elde edilmiştir. Çok katmanlı düzlemsel ortam için elde edilen analitik çözüm katmanlı düzlemsel green fonksiyonlarına dayanmaktadır. Çok katmanlı düzlemsel modelleme meme, deri ve karın bölgesi görüntülemelerine uygun bir modellemedir. Elde edilen analitik çözüm ile literatürde var olan homojen ortam varsayımına dayanan çözüm her katmanda noktasal kaynak alınarak sayısal olarak karşılaştırılmıştır.
Çok katmanlı silindirik yapılar için termoakustik dalga denkleminin ters çözümü
(IEEE, 2017-06-27) Elmas, Demet; Ünalmış Uzun, Banu; İdemen, Mehmet Mithat; Karaman, Mustafa
Termoakustik görüntüleme, elektromanyetik enerji uyarımı ile ultrason dalgaları oluşumunu sağlayan yeni bir yöntemdir. Bu sistemin görüntüleme işlemi termoakustik dalga denkleminin ters çözümüne dayanmaktadır. Ters çözümde görüntülenecek dokunun homojen yapıda olduğu varsayımı, görüntü kalitesinin azalmasına neden olur. Bu çalışmada, meme ve beyinin görüntülemesinde uygulanabilecek üç boyutlu eş merkezli silindirik çok katmanlı yapılar için termoakustik dalga denkleminin analitik ters çözümü elde edilmiştir. Çözümü sayısal olarak test etmek için, noktasal kaynaklar içeren üç katmanlı fantom kullanılarak numerik simulasyonlar elde edilmiştir.
Cross-sectional thermoacoustic imaging using multi-layer cylindrical media
(IEEE, 2017-11-10) Elmas, Demet; Ünalmış Uzun, Banu; İdemen, Mehmet Mithat; Karaman, Mustafa
For cross-sectional two-dimensional thermoacustic imaging of breast and brain, we explored solution of the wave equation using layered tissue model consisting of concentric annular layers on a cylindrical cross-section. To obtain the forward and inverse solutions of the thermoacoustic wave equation, we derived the Green's function involving Bessel and Hankel functions by employing the geometrical and acoustic parameters (densities and velocities) of layered media together with temporal initial condition, radiation conditions and continuity conditions on the layers' boundaries. The image reconstruction based on this approach involves the layer parameters as the apriori information which can be estimated from the acquired thermoacoustic data. To test and compare our layered solution with conventional solution based on homogeneous medium assumption, we performed simulations using numerical test phantoms consisting of sources distributed in the layered structure.
Damar içi öne bakan ultrasonik görüntüleme için eşdeğer dizi örnekleme yöntemleri
(IEEE, 2009-06-26) Tekeş, Coşkun; Karaman, Mustafa
Damar içi öne bakan ultrasonik görüntüleme gerçek zamanlı hacimsel (üç boyutlu) görüntülemeye imkan vermesi bakımından yaygın olarak kullanılmaktadır. Damar içi görüntülemede fiziksel boyutların küçük olması nedeniyle alıcı-verici kanal sayısı çok sınırlanmakta ve dolayısıyla yapay evreli dizi teknikleri kullanılmaktadır. Öte yandan, harekete bağlı görüntü bozukluklarını azaltmak için işaret gönderme alma adım sayısının azaltılması gerekmektedir. Bu, eşdeğer dizideki fazlalık frekans bileşenleri azaltılarak sağlanabilir. Bu çalışmada, eşdeğer dizideki fazlalık frekans bileşenlerinin azaltılmasına dayalı farklı örnekleme teknikleri incelenmiştir. Bu tekniklerin görüntü kalitesi 64 elemanlı bir halkasal dizinin asıl ve kontrol eşdeğer dizileri referans alınarak karşılaştırmalı olarak irdelenmiştir. Benzetim sonuçları 64 elemanlı bir halka dizi için 2049 asıl küme, 350 azaltılmış küme 40 dB içinde eşdeğer performans vermektedir.
Damariçi yanal kesit görüntüleme için farklı prob yapılarının incelenmesi
(IEEE, 2009-06-26) Şişman, Alper; Karaman, Mustafa
Bu çalışmada dönen bir şaftın yanal yüzeyine yerleştirilmiş 8 adet içiçe halka elemanlardan oluşan yana bakan görüntüleme için yeni bir kateter yapısı incelenmiştir. Bu Katater mimarisi basit bir dizi önü alıcı verici elektroniği ile değişken odaklama olanağı sağlamaktadır. Önerilen mimari, mevcut iki farklı kateter mimarisiyle benzetim sonuçları ile karşılaştırmalı olarak incelenmiştir. Benzetimlerde görüntüleme kateter çapı 1mm alınmış, farklı derinlikler ve açılar için 3 noktasal yansıtıcı ile NDF çıkarılmıştır.
Design of a front-end integrated circuit for 3D acoustic imaging using 2D CMUT arrays
(IEEE-INST Electrical Electronics Engineers Inc, 2005-12) Çiçek, İhsan; Bozkurt, Ayhan; Karaman, Mustafa
Integration of front-end electronics with 2D capacitive micromachined ultrasonic transducer (CMUT) arrays has been a challenging issue due to the small element size and large channel count. We present design and verification of a front-end drive-readout integrated circuit for 3D ultrasonic imaging using 2D CMUT arrays. The circuit cell dedicated to a single CMUT array element consists of a high-voltage pulser and a low-noise readout amplifier. To analyze the circuit cell together with the CMUT element, we developed an electrical CMUT model with parameters derived through finite element analysis, and performed both the pre- and postlayout verification. An experimental chip consisting of 4 x 4 array of the designed circuit cells, each cell occupying a 200 x 200 mu m(2) area, was formed for the initial test studies and scheduled for fabrication in 0.8 mu m, 50 V CMOS technology. The designed circuit is suitable for integration with CMUT arrays through flip-chip bonding and the CMUT-on-CMOS process.
Dual electrode capacitive micromachined ultrasonic transducer array for 1-D intracardiac echocardiography (ICE)
(American Society of Mechanical Engineers (ASME), 2007) Güldiken, Rasim Oytun; Zahorian, Jaime S.; Karaman, Mustafa; Değertekin, Fahrettin Levent
We designed and fabricated a 64 element 1-D linear dual electrode Capacitive Micromachined Ultrasonic Transducer (CMUT) array operating at 9.5 MHz for Intracardiac Echocardiography (ICE). The dual electrode CMUT structure increases the overall sensitivity by 12.6dB (6.2dB in receive sensitivity; 6.4dB in output pressure) when compared to optimized single electrode CMUT. We report peak output pressure of 2.3MPa on the CMUT surface when 170V AC and 180V DC is applied. This significant performance increase makes the CMUT more competitive with their piezoelectric counterparts.
Dual-annular-ring CMUT array for forward-looking IVUS imaging
(IEEE, 2006) Güldiken, Rasim Oytun; Zahorian, Jaime; Balantekin, Müjdat; Değertekin, Fahrettin Levent; Tekeş, Coşkun; Şişman, Alper; Karaman, Mustafa
We investigate a dual-annular-ring CMUT array configuration for forward-looking intravascular ultrasound (FL-IVUS) imaging. The array consists of separate, concentric transmit and receive ring arrays built on the same silicon substrate. This configuration has the potential for independent optimization of each array and uses the silicon area more effectively without any particular drawback. We designed and fabricated a 1mm diameter test array which consists of 24 transmit and 32 receive elements. We investigated synthetic phased array beamforming with a non-redundant subset (if transmit-receive element pairs of the dual-annular-ring array. For imaging experiments, we designed and constructed a programmable FPGA-based data acquisition and phased array beamforming system. Pulse-echo measurements along with imaging simulations suggest that dual-ring-annular array should provide performance suitable for real-time FLAVUS applications.
An endoscopie imaging system based on a two-dimensional CMUT array: real-time imaging results
(IEEE, 2005) Wygant, Ira O.; Zhuang, Xuefeng; Yeh, David T.; Vaithilingam, Srikant; Nikoozadeh, Amin; Oralkan, Ömer; Ergün, Arif Sanlı; Karaman, Mustafa; Khuri-Yakub, Butrus Thomas
Real-time catheter-based ultrasound imaging tools are needed for diagnosis and image-guided procedures. The continued development of these tools is partially limited by the difficulty of fabricating two-dimensional array geometries of piezoelectric transducers. Using capacitive micromachined ultrasonic transducer (CMUT) technology, transducer arrays with widely varying geometries, high frequencies, and wide bandwidths can be fabricated. A volumetric ultrasound imaging system based on a two-dimensional, 16×l6-element, CMUT array is presented. Transducer arrays with operating frequencies ranging from 3 MHz to 7.5 MHz were fabricated for this system. The transducer array including DC bias pads measures 4 mm by 4.7 mm. The transducer elements are connected to flip-chip bond pads on the array back side with 400-?m long through-wafer interconnects. The array is flip-chip bonded to a custom-designed integrated circuit (IC) that comprises the front-end electronics. Integrating the front-end electronics with the transducer array reduces the effects of cable capacitance on the transducer's performance and provides a compact means of connecting to the transducer elements. The front-end IC provides a 27-V pulser and 10-MHz bandwidth amplifier for each element of the array. An FPGA-based data acquisition system is used for control and data acquisition. Output pressure of 230 kPa was measured for the integrated device. A receive sensitivity of 125 mV/kPa was measured at the output of the amplifier. Amplifier output noise at 5 Mhz is 112 nV/?Hz. Volumetric images of a wire phantom and vessel phantom are presented. Volumetric data for a wire phantom was acquired in real-time at 30 frames per second.
Evaluation of CMUT annular arrays for side-looking IVUS
(IEEE, 2009) Şişman, Alper; Zahorian, Jaime S.; Gürün, Gökçe; Karaman, Mustafa; Balantekin, Müjdat; Değertekin, Fahrettin Levent; Hasler, Paul E.
Side-looking (SL) IVUS probes are extensively used for management of cardiovascular diseases. Currently SL-IVUS imaging probes use either a single rotating transducer element or solid-state arrays. Probes with single rotating piezoelectric transducer have simple front-end, but have fixed focused operation, and suffers from motion artifacts. Solid-state SL-IVUS imaging probes use piezoelectric transducer arrays and electronic beam-forming. Synthetic phased array processing of signals detected with small-sized elements in these arrays limits the SNR achievable with these probes. In this study, we explore a new SL-IVUS probe architecture employing rotating phased annular CMUT arrays. We tested and compared imaging performance of the existing and proposed probe configurations through simulated point spread functions. We also two fabricated sample annular array designs operating at 20-MHz and 50-MHz. Our experimental measurements on the 20-MHz array in oil shows 105% fractional bandwidth. The 50-MHz array with parylene coating shows approximately 40% fractional bandwidth measured in water. We also present imaging results acquired from wire-targets to test the experimental point-spread functions.

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