AIDT 온디바이스 STEM 탐침 증강 라만 분광(TERS) 플라즈모닉 핫스팟 및 단분자 식별 서보 엔진

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.Ters
{
    public readonly ref struct TersHotspotState
    {
        public readonly double TipSampleGapNm;       // 탐침-시료 간격 d (nm)
        public readonly double FieldEnhancementG;    // 전자기장 증폭 계수 g_EM
        public readonly double RamanEnhancementFactor;// 라만 증폭도 (g_EM^4)
        public readonly double HotspotRadiusNm;      // 플라즈모닉 핫스팟 유효 반경 (nm)
        public readonly double TunnelingCurrentNa;   // 양자 터널링 전류 (nA)
        public readonly double PeakRamanCps;         // 검출 라만 카운트율 (CPS)

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public TersHotspotState(double gap, double gEm, double ef, double radius, double current, double cps)
        {
            TipSampleGapNm = gap;
            FieldEnhancementG = gEm;
            RamanEnhancementFactor = ef;
            HotspotRadiusNm = radius;
            TunnelingCurrentNa = current;
            PeakRamanCps = cps;
        }
    }

    public ref struct TersSpectroscopyEngine
    {
        private const double DielectricAgReal = -16.5; // 은(Ag) 633nm 유전율 실수부
        private const double DielectricAgImag = 0.5;   // 허수부
        private const double WorkFunctionEv = 4.5;     // 터널링 장벽 (eV)

        private readonly double _tipRadiusNm;         // 탐침 반경 R (nm)
        private double _currentGapNm;                 // 현재 간극 거리 (nm)
        private double _laserPowerMw;                 // 집속 레이저 출력 (mW)

        public TersSpectroscopyEngine(double tipRadiusNm = 12.0, double initGapNm = 1.0, double laserMw = 2.0)
        {
            _tipRadiusNm = tipRadiusNm;
            _currentGapNm = initGapNm;
            _laserPowerMw = laserMw;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public TersHotspotState StepServo(double targetGapNm, double piezoCorrectionNm, double dtSec)
        {
            _currentGapNm = Math.Clamp(_currentGapNm + piezoCorrectionNm, 0.2, 5.0);

            // 1. 번개도체 기하학적 인자 및 정전 쌍극자장 증폭 계수 계산
            double geometricFactor = Math.Pow(1.0 + _tipRadiusNm / (_currentGapNm + _tipRadiusNm), 3.0);
            double plasmonResonanceFactor = Math.Abs((DielectricAgReal - 1.0) / (DielectricAgReal + 2.0));
            double gEm = plasmonResonanceFactor * geometricFactor;

            // 2. 양자 터널링 소광 한계 (d < 0.5 nm 영역에서 비국소 양자 터널링 감쇠)
            if (_currentGapNm < 0.5)
            {
                double quantumQuench = Math.Exp(-(_currentGapNm - 0.5) * 6.0);
                gEm /= (1.0 + quantumQuench);
            }

            // 3. E^4 라만 증폭율 및 유효 핫스팟 반경
            double ramanEnhancement = Math.Pow(gEm, 4.0);
            double hotspotRadius = Math.Sqrt(_tipRadiusNm * _currentGapNm) * 0.5;

            // 4. 터널링 전류 시뮬레이션 (Simmons 1D 포뮬러 단순화)
            double tunnelingCurrent = 10.0 * Math.Exp(-1.025 * Math.Sqrt(WorkFunctionEv) * (_currentGapNm * 10.0));

            // 5. 단분자 라만 카운트율 계산
            double peakCps = 50.0 * (_laserPowerMw / 2.0) * (ramanEnhancement / 1e7);

            return new TersHotspotState(
                gap: _currentGapNm,
                gEm: gEm,
                ef: ramanEnhancement,
                radius: hotspotRadius,
                current: tunnelingCurrent,
                cps: peakCps
            );
        }
    }
}