Efek Circular Dichroism pada Metamaterial Chiral Planar

Juliasih Partini

Sari


Abstrak – Penelitian ini mengkaji efek circular dichroism pada metamaterial chiral planar. Bidang polarisasi akan terotasi ketika cahaya yang terpolarisasi linear melewati metamaterial chiral planar. Pada efek circular dichroism, cahaya yang terpolarisasi circular putaran kanan dan putaran kiri akan mempunyai perbedaan absorpsi dalam interaksinya dengan partikel penyusun metamaterial chiral planar. Spektrum eliptisitas metamaterial chiral planar menunjukkan eliptisitas bahan yang bernilai positif untuk sampel putar kanan dan bernilai negatif untuk sampel putar kiri. Nilai eliptisitas diperoleh sebesar maksimal +0,3 dan -0,3 terjadi pada frekuensi 1,29 THz. Eliptisitas maksimum menunjukkan adanya kopling antara foton dengan plasmon permukaan sampel. Polaritas yang berlawanan menunjukkan perbedaan absorbansi antara sampel putar kanan dan sampel putar kiri. Hasil tersebut juga menunjukkan adanya perubahan polarisasi linear pada laser femtosekon menjadi polarisasi eliptik pada  gelombang THz hasil emisi sampel metamaterial chiral planar. Kemampuan metamaterial chiral planar dalam memutar bidang polarisasi dan merubah menjadi polarisasi circular menjadikan bahan ini layak dijadikan alternatif polarisator dalam ranah terahertz.

 

Kata kunci: metamaterial, circular dichroism, chirality, polarisasi, eliptisitas

Abstract – This paper describes the circular dichroism effect on planar chiral metamaterial. When a linearly polarized light passes through the planar chiral metamaterial, its polarization plane will rotate. On the circular dichroism effect, the right and left circulary polarized light will have different absorption due to its interaction with a planar chiral metamaterial. The ellipticity spectrum of a planar chiral metamaterial sample shows a positive ellipticity value for the counter clock-wise sample and a negative value for the clock-wise sample. The maximum ellipticity value is determine as +0,3 and -0,3 at frequency of 1,29 THz. The values show the existence of a coupling between photon and the sample surface plasmon. The opposite polarity indicates that the clock-wise and the counter clock-wise sample have different absorbance. The determined ellipticity value also reveals that the linearly polarized femtosecond laser light has transformed to elliptical polarized THz wave on a planar chiral metamaterial sample emission. The planar chiral metamaterial capability to rotate the polarization plane into circulary polarized wave, makes the material can be considered as an alternative polarizer in terahertz field. 

Key words: metamaterial, circular dichroism, chirality, polarization, ellipticity

Kata Kunci


metamaterial; circular dichroism; chirality; polarisasi; eliptisitas

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Referensi


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DOI: https://doi.org/10.35895/rf.v2i2.113

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